By Huda Eid Abdelwahab Nowar

1 Introduction of carbohydrates

Carbohydrate is a organic compound Carbohydrates are hydrates of carbon technically they are polyhydroxy aldehydes and ketones Carbohydrates are also known as saccharides the word saccharide comes from Greek word sakkron which means sugar Polyhydroxy aldehydes or ketones or substances that yield such compounds on hydrolysis

bull (CH2O)n

bull 70-80 human energy needs bull gt90 dry matter of plants

Properties of Carbohydrates

General properties of carbohydrates Carbohydrates act as energy reserves also stores fuels and metabolic intermediates

Ribose and deoxyribose sugars forms the structural frame of the genetic material RNA and DNA

Polysaccharides like cellulose are the structural elements in the cell walls of bacteria and plants

Carbohydrates are linked to proteins and lipids that play important roles in cell interactions

Carbohydrates are organic compounds they are aldehydes or ketones with many hydroxyl groups

Physical Properties of Carbohydrate

Steroisomerism ndash Compounds having same structural formula but they differ in spatial configuration Example Glucose has two isomers with respect to penultimate carbon atom They are D-glucose and L-glucose

Optical Activity - It is the rotation of plane polarized light forming (+) glucose and (-) glucose

Diastereo isomers - It the configurational changes with regard to C2 C3 or C4 in glucose Example Mannose galactose

Annomerism - It is the spatial configuration with respect to the first carbon atom in aldoses and second carbon atom in ketoses

2 Stereochemistry and Configuration

STEREOISOMERS

Compounds having same structural formula but differ in spatial configuration(Chiral center) Asymmetric Carbon atom Attached to four different atoms or groups

Vant Hoffrsquos rule The possible isomers (2n) of a given compound is determined by the number of asymmetric carbon atoms (n)

Reference C atom Penultimate C atom around which mirror images are formed

RS System Suppose you had a model of one of these glucose

enantiomers in your hand You could of course use the RS ( Prelog) system to describe the configuration of one or more of the asymmetric carbon atoms

7

Even though the RS system is widely accepted today as a standard for designating configuration the configuration of carbohydrates as well as those of amino acids and many other compounds in biochemistry is commonly designated by the DL system proposed by Emil Fischer in 1891

8

CHO

CH OH

CH2OH

CHO

C HHO

CH2OH

(R)-Glyceraldehyde (S)-Glyceraldehyde

4 C 3

1

2

4 C 2

1

3

(S) (R)

The DL is ( Rosanoff) systemDextrorotatory (+) If sugar solution turns the plane of polarized light to rightLevorotatory (ndash) If the sugar solution turns the plane of polarized light to leftRacemic mixture Equimolar mixture of optical isomers has no net rotation

1 Monosaccharides contain one or more asymmetric C-atoms get D- and L-forms where D- and L- designate absolute configuration

2 D-form -OH group is attached to the right of the asymmetric carbon3 L-form -OH group is attached to the left of the asymmetric carbon4 If there is more than one chiral C-atom absolute configuration of chiral C

furthest away from carbonyl group determines whether D- or L-

Optical activityD and L

configurations

examples of chiral Carbon atoms

Highest numbered streocente

r

The aldo hexoses have four asymmetric carbons and therefore exist as 16 possible stereo isomers

11

HOH2C

OH

HC

OH

HC

OH

HC

HC

OH

CH

O

Aldohexosesfour asymmetric carbons

24 = 16 stereoisomers

1 2 3 4

Diastereomers Each diastereomer is a different carbohydrate with different properties

known by a different name

Each of the monosaccharides has an enantiomer For example the two enantiomers of glucose have the following structures

12

HC

OHH

HHO

OHH

OHH

CH2OH

HC

HO H

H OH

HO H

HO H

CH2OH

O

Enantiomers of glucose

D - L -

O

EPIMERISMSugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)

Chemists commonly use two-dimensional representations called Fischer projections to show the configuration of carbohydrates

A Fischer projection is used to differentiate between L- and D- molecules On a Fischer projection the penultimate carbon of D sugars are depicted with hydrogen on the left and hydroxyl on the right L sugars will be shown with the hydrogen on the right and the hydroxyl on the left

Fischer Projection Formulas(ACyclic Form of Carbohydrate)

The Fischer projection devised by Hermann Emil Fischer in 1891 is a two-dimensional representation of a three-

dimensional organic molecule by projection15

The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center

16

Paper plane

When relating one Fischer projection to another its important to realise that it may only be manipulated within the 2D plane in which it is drawn (that is it may not be rotated within 3D space) and even then it can only rotated in the plane it is drawn (2D) by 180o

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

1 Introduction of carbohydrates

Carbohydrate is a organic compound Carbohydrates are hydrates of carbon technically they are polyhydroxy aldehydes and ketones Carbohydrates are also known as saccharides the word saccharide comes from Greek word sakkron which means sugar Polyhydroxy aldehydes or ketones or substances that yield such compounds on hydrolysis

bull (CH2O)n

bull 70-80 human energy needs bull gt90 dry matter of plants

Properties of Carbohydrates

General properties of carbohydrates Carbohydrates act as energy reserves also stores fuels and metabolic intermediates

Ribose and deoxyribose sugars forms the structural frame of the genetic material RNA and DNA

Polysaccharides like cellulose are the structural elements in the cell walls of bacteria and plants

Carbohydrates are linked to proteins and lipids that play important roles in cell interactions

Carbohydrates are organic compounds they are aldehydes or ketones with many hydroxyl groups

Physical Properties of Carbohydrate

Steroisomerism ndash Compounds having same structural formula but they differ in spatial configuration Example Glucose has two isomers with respect to penultimate carbon atom They are D-glucose and L-glucose

Optical Activity - It is the rotation of plane polarized light forming (+) glucose and (-) glucose

Diastereo isomers - It the configurational changes with regard to C2 C3 or C4 in glucose Example Mannose galactose

Annomerism - It is the spatial configuration with respect to the first carbon atom in aldoses and second carbon atom in ketoses

2 Stereochemistry and Configuration

STEREOISOMERS

Compounds having same structural formula but differ in spatial configuration(Chiral center) Asymmetric Carbon atom Attached to four different atoms or groups

Vant Hoffrsquos rule The possible isomers (2n) of a given compound is determined by the number of asymmetric carbon atoms (n)

Reference C atom Penultimate C atom around which mirror images are formed

RS System Suppose you had a model of one of these glucose

enantiomers in your hand You could of course use the RS ( Prelog) system to describe the configuration of one or more of the asymmetric carbon atoms

7

Even though the RS system is widely accepted today as a standard for designating configuration the configuration of carbohydrates as well as those of amino acids and many other compounds in biochemistry is commonly designated by the DL system proposed by Emil Fischer in 1891

8

CHO

CH OH

CH2OH

CHO

C HHO

CH2OH

(R)-Glyceraldehyde (S)-Glyceraldehyde

4 C 3

1

2

4 C 2

1

3

(S) (R)

The DL is ( Rosanoff) systemDextrorotatory (+) If sugar solution turns the plane of polarized light to rightLevorotatory (ndash) If the sugar solution turns the plane of polarized light to leftRacemic mixture Equimolar mixture of optical isomers has no net rotation

1 Monosaccharides contain one or more asymmetric C-atoms get D- and L-forms where D- and L- designate absolute configuration

2 D-form -OH group is attached to the right of the asymmetric carbon3 L-form -OH group is attached to the left of the asymmetric carbon4 If there is more than one chiral C-atom absolute configuration of chiral C

furthest away from carbonyl group determines whether D- or L-

Optical activityD and L

configurations

examples of chiral Carbon atoms

Highest numbered streocente

r

The aldo hexoses have four asymmetric carbons and therefore exist as 16 possible stereo isomers

11

HOH2C

OH

HC

OH

HC

OH

HC

HC

OH

CH

O

Aldohexosesfour asymmetric carbons

24 = 16 stereoisomers

1 2 3 4

Diastereomers Each diastereomer is a different carbohydrate with different properties

known by a different name

Each of the monosaccharides has an enantiomer For example the two enantiomers of glucose have the following structures

12

HC

OHH

HHO

OHH

OHH

CH2OH

HC

HO H

H OH

HO H

HO H

CH2OH

O

Enantiomers of glucose

D - L -

O

EPIMERISMSugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)

Chemists commonly use two-dimensional representations called Fischer projections to show the configuration of carbohydrates

A Fischer projection is used to differentiate between L- and D- molecules On a Fischer projection the penultimate carbon of D sugars are depicted with hydrogen on the left and hydroxyl on the right L sugars will be shown with the hydrogen on the right and the hydroxyl on the left

Fischer Projection Formulas(ACyclic Form of Carbohydrate)

The Fischer projection devised by Hermann Emil Fischer in 1891 is a two-dimensional representation of a three-

dimensional organic molecule by projection15

The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center

16

Paper plane

When relating one Fischer projection to another its important to realise that it may only be manipulated within the 2D plane in which it is drawn (that is it may not be rotated within 3D space) and even then it can only rotated in the plane it is drawn (2D) by 180o

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Properties of Carbohydrates

General properties of carbohydrates Carbohydrates act as energy reserves also stores fuels and metabolic intermediates

Ribose and deoxyribose sugars forms the structural frame of the genetic material RNA and DNA

Polysaccharides like cellulose are the structural elements in the cell walls of bacteria and plants

Carbohydrates are linked to proteins and lipids that play important roles in cell interactions

Carbohydrates are organic compounds they are aldehydes or ketones with many hydroxyl groups

Physical Properties of Carbohydrate

Steroisomerism ndash Compounds having same structural formula but they differ in spatial configuration Example Glucose has two isomers with respect to penultimate carbon atom They are D-glucose and L-glucose

Optical Activity - It is the rotation of plane polarized light forming (+) glucose and (-) glucose

Diastereo isomers - It the configurational changes with regard to C2 C3 or C4 in glucose Example Mannose galactose

Annomerism - It is the spatial configuration with respect to the first carbon atom in aldoses and second carbon atom in ketoses

2 Stereochemistry and Configuration

STEREOISOMERS

Compounds having same structural formula but differ in spatial configuration(Chiral center) Asymmetric Carbon atom Attached to four different atoms or groups

Vant Hoffrsquos rule The possible isomers (2n) of a given compound is determined by the number of asymmetric carbon atoms (n)

Reference C atom Penultimate C atom around which mirror images are formed

RS System Suppose you had a model of one of these glucose

enantiomers in your hand You could of course use the RS ( Prelog) system to describe the configuration of one or more of the asymmetric carbon atoms

7

Even though the RS system is widely accepted today as a standard for designating configuration the configuration of carbohydrates as well as those of amino acids and many other compounds in biochemistry is commonly designated by the DL system proposed by Emil Fischer in 1891

8

CHO

CH OH

CH2OH

CHO

C HHO

CH2OH

(R)-Glyceraldehyde (S)-Glyceraldehyde

4 C 3

1

2

4 C 2

1

3

(S) (R)

The DL is ( Rosanoff) systemDextrorotatory (+) If sugar solution turns the plane of polarized light to rightLevorotatory (ndash) If the sugar solution turns the plane of polarized light to leftRacemic mixture Equimolar mixture of optical isomers has no net rotation

1 Monosaccharides contain one or more asymmetric C-atoms get D- and L-forms where D- and L- designate absolute configuration

2 D-form -OH group is attached to the right of the asymmetric carbon3 L-form -OH group is attached to the left of the asymmetric carbon4 If there is more than one chiral C-atom absolute configuration of chiral C

furthest away from carbonyl group determines whether D- or L-

Optical activityD and L

configurations

examples of chiral Carbon atoms

Highest numbered streocente

r

The aldo hexoses have four asymmetric carbons and therefore exist as 16 possible stereo isomers

11

HOH2C

OH

HC

OH

HC

OH

HC

HC

OH

CH

O

Aldohexosesfour asymmetric carbons

24 = 16 stereoisomers

1 2 3 4

Diastereomers Each diastereomer is a different carbohydrate with different properties

known by a different name

Each of the monosaccharides has an enantiomer For example the two enantiomers of glucose have the following structures

12

HC

OHH

HHO

OHH

OHH

CH2OH

HC

HO H

H OH

HO H

HO H

CH2OH

O

Enantiomers of glucose

D - L -

O

EPIMERISMSugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)

Chemists commonly use two-dimensional representations called Fischer projections to show the configuration of carbohydrates

A Fischer projection is used to differentiate between L- and D- molecules On a Fischer projection the penultimate carbon of D sugars are depicted with hydrogen on the left and hydroxyl on the right L sugars will be shown with the hydrogen on the right and the hydroxyl on the left

Fischer Projection Formulas(ACyclic Form of Carbohydrate)

The Fischer projection devised by Hermann Emil Fischer in 1891 is a two-dimensional representation of a three-

dimensional organic molecule by projection15

The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center

16

Paper plane

When relating one Fischer projection to another its important to realise that it may only be manipulated within the 2D plane in which it is drawn (that is it may not be rotated within 3D space) and even then it can only rotated in the plane it is drawn (2D) by 180o

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Physical Properties of Carbohydrate

Steroisomerism ndash Compounds having same structural formula but they differ in spatial configuration Example Glucose has two isomers with respect to penultimate carbon atom They are D-glucose and L-glucose

Optical Activity - It is the rotation of plane polarized light forming (+) glucose and (-) glucose

Diastereo isomers - It the configurational changes with regard to C2 C3 or C4 in glucose Example Mannose galactose

Annomerism - It is the spatial configuration with respect to the first carbon atom in aldoses and second carbon atom in ketoses

2 Stereochemistry and Configuration

STEREOISOMERS

Compounds having same structural formula but differ in spatial configuration(Chiral center) Asymmetric Carbon atom Attached to four different atoms or groups

Vant Hoffrsquos rule The possible isomers (2n) of a given compound is determined by the number of asymmetric carbon atoms (n)

Reference C atom Penultimate C atom around which mirror images are formed

RS System Suppose you had a model of one of these glucose

enantiomers in your hand You could of course use the RS ( Prelog) system to describe the configuration of one or more of the asymmetric carbon atoms

7

Even though the RS system is widely accepted today as a standard for designating configuration the configuration of carbohydrates as well as those of amino acids and many other compounds in biochemistry is commonly designated by the DL system proposed by Emil Fischer in 1891

8

CHO

CH OH

CH2OH

CHO

C HHO

CH2OH

(R)-Glyceraldehyde (S)-Glyceraldehyde

4 C 3

1

2

4 C 2

1

3

(S) (R)

The DL is ( Rosanoff) systemDextrorotatory (+) If sugar solution turns the plane of polarized light to rightLevorotatory (ndash) If the sugar solution turns the plane of polarized light to leftRacemic mixture Equimolar mixture of optical isomers has no net rotation

1 Monosaccharides contain one or more asymmetric C-atoms get D- and L-forms where D- and L- designate absolute configuration

2 D-form -OH group is attached to the right of the asymmetric carbon3 L-form -OH group is attached to the left of the asymmetric carbon4 If there is more than one chiral C-atom absolute configuration of chiral C

furthest away from carbonyl group determines whether D- or L-

Optical activityD and L

configurations

examples of chiral Carbon atoms

Highest numbered streocente

r

The aldo hexoses have four asymmetric carbons and therefore exist as 16 possible stereo isomers

11

HOH2C

OH

HC

OH

HC

OH

HC

HC

OH

CH

O

Aldohexosesfour asymmetric carbons

24 = 16 stereoisomers

1 2 3 4

Diastereomers Each diastereomer is a different carbohydrate with different properties

known by a different name

Each of the monosaccharides has an enantiomer For example the two enantiomers of glucose have the following structures

12

HC

OHH

HHO

OHH

OHH

CH2OH

HC

HO H

H OH

HO H

HO H

CH2OH

O

Enantiomers of glucose

D - L -

O

EPIMERISMSugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)

Chemists commonly use two-dimensional representations called Fischer projections to show the configuration of carbohydrates

A Fischer projection is used to differentiate between L- and D- molecules On a Fischer projection the penultimate carbon of D sugars are depicted with hydrogen on the left and hydroxyl on the right L sugars will be shown with the hydrogen on the right and the hydroxyl on the left

Fischer Projection Formulas(ACyclic Form of Carbohydrate)

The Fischer projection devised by Hermann Emil Fischer in 1891 is a two-dimensional representation of a three-

dimensional organic molecule by projection15

The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center

16

Paper plane

When relating one Fischer projection to another its important to realise that it may only be manipulated within the 2D plane in which it is drawn (that is it may not be rotated within 3D space) and even then it can only rotated in the plane it is drawn (2D) by 180o

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

2 Stereochemistry and Configuration

STEREOISOMERS

Compounds having same structural formula but differ in spatial configuration(Chiral center) Asymmetric Carbon atom Attached to four different atoms or groups

Vant Hoffrsquos rule The possible isomers (2n) of a given compound is determined by the number of asymmetric carbon atoms (n)

Reference C atom Penultimate C atom around which mirror images are formed

RS System Suppose you had a model of one of these glucose

enantiomers in your hand You could of course use the RS ( Prelog) system to describe the configuration of one or more of the asymmetric carbon atoms

7

Even though the RS system is widely accepted today as a standard for designating configuration the configuration of carbohydrates as well as those of amino acids and many other compounds in biochemistry is commonly designated by the DL system proposed by Emil Fischer in 1891

8

CHO

CH OH

CH2OH

CHO

C HHO

CH2OH

(R)-Glyceraldehyde (S)-Glyceraldehyde

4 C 3

1

2

4 C 2

1

3

(S) (R)

The DL is ( Rosanoff) systemDextrorotatory (+) If sugar solution turns the plane of polarized light to rightLevorotatory (ndash) If the sugar solution turns the plane of polarized light to leftRacemic mixture Equimolar mixture of optical isomers has no net rotation

1 Monosaccharides contain one or more asymmetric C-atoms get D- and L-forms where D- and L- designate absolute configuration

2 D-form -OH group is attached to the right of the asymmetric carbon3 L-form -OH group is attached to the left of the asymmetric carbon4 If there is more than one chiral C-atom absolute configuration of chiral C

furthest away from carbonyl group determines whether D- or L-

Optical activityD and L

configurations

examples of chiral Carbon atoms

Highest numbered streocente

r

The aldo hexoses have four asymmetric carbons and therefore exist as 16 possible stereo isomers

11

HOH2C

OH

HC

OH

HC

OH

HC

HC

OH

CH

O

Aldohexosesfour asymmetric carbons

24 = 16 stereoisomers

1 2 3 4

Diastereomers Each diastereomer is a different carbohydrate with different properties

known by a different name

Each of the monosaccharides has an enantiomer For example the two enantiomers of glucose have the following structures

12

HC

OHH

HHO

OHH

OHH

CH2OH

HC

HO H

H OH

HO H

HO H

CH2OH

O

Enantiomers of glucose

D - L -

O

EPIMERISMSugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)

Chemists commonly use two-dimensional representations called Fischer projections to show the configuration of carbohydrates

A Fischer projection is used to differentiate between L- and D- molecules On a Fischer projection the penultimate carbon of D sugars are depicted with hydrogen on the left and hydroxyl on the right L sugars will be shown with the hydrogen on the right and the hydroxyl on the left

Fischer Projection Formulas(ACyclic Form of Carbohydrate)

The Fischer projection devised by Hermann Emil Fischer in 1891 is a two-dimensional representation of a three-

dimensional organic molecule by projection15

The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center

16

Paper plane

When relating one Fischer projection to another its important to realise that it may only be manipulated within the 2D plane in which it is drawn (that is it may not be rotated within 3D space) and even then it can only rotated in the plane it is drawn (2D) by 180o

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

STEREOISOMERS

Compounds having same structural formula but differ in spatial configuration(Chiral center) Asymmetric Carbon atom Attached to four different atoms or groups

Vant Hoffrsquos rule The possible isomers (2n) of a given compound is determined by the number of asymmetric carbon atoms (n)

Reference C atom Penultimate C atom around which mirror images are formed

RS System Suppose you had a model of one of these glucose

enantiomers in your hand You could of course use the RS ( Prelog) system to describe the configuration of one or more of the asymmetric carbon atoms

7

Even though the RS system is widely accepted today as a standard for designating configuration the configuration of carbohydrates as well as those of amino acids and many other compounds in biochemistry is commonly designated by the DL system proposed by Emil Fischer in 1891

8

CHO

CH OH

CH2OH

CHO

C HHO

CH2OH

(R)-Glyceraldehyde (S)-Glyceraldehyde

4 C 3

1

2

4 C 2

1

3

(S) (R)

The DL is ( Rosanoff) systemDextrorotatory (+) If sugar solution turns the plane of polarized light to rightLevorotatory (ndash) If the sugar solution turns the plane of polarized light to leftRacemic mixture Equimolar mixture of optical isomers has no net rotation

1 Monosaccharides contain one or more asymmetric C-atoms get D- and L-forms where D- and L- designate absolute configuration

2 D-form -OH group is attached to the right of the asymmetric carbon3 L-form -OH group is attached to the left of the asymmetric carbon4 If there is more than one chiral C-atom absolute configuration of chiral C

furthest away from carbonyl group determines whether D- or L-

Optical activityD and L

configurations

examples of chiral Carbon atoms

Highest numbered streocente

r

The aldo hexoses have four asymmetric carbons and therefore exist as 16 possible stereo isomers

11

HOH2C

OH

HC

OH

HC

OH

HC

HC

OH

CH

O

Aldohexosesfour asymmetric carbons

24 = 16 stereoisomers

1 2 3 4

Diastereomers Each diastereomer is a different carbohydrate with different properties

known by a different name

Each of the monosaccharides has an enantiomer For example the two enantiomers of glucose have the following structures

12

HC

OHH

HHO

OHH

OHH

CH2OH

HC

HO H

H OH

HO H

HO H

CH2OH

O

Enantiomers of glucose

D - L -

O

EPIMERISMSugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)

Chemists commonly use two-dimensional representations called Fischer projections to show the configuration of carbohydrates

A Fischer projection is used to differentiate between L- and D- molecules On a Fischer projection the penultimate carbon of D sugars are depicted with hydrogen on the left and hydroxyl on the right L sugars will be shown with the hydrogen on the right and the hydroxyl on the left

Fischer Projection Formulas(ACyclic Form of Carbohydrate)

The Fischer projection devised by Hermann Emil Fischer in 1891 is a two-dimensional representation of a three-

dimensional organic molecule by projection15

The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center

16

Paper plane

When relating one Fischer projection to another its important to realise that it may only be manipulated within the 2D plane in which it is drawn (that is it may not be rotated within 3D space) and even then it can only rotated in the plane it is drawn (2D) by 180o

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

RS System Suppose you had a model of one of these glucose

enantiomers in your hand You could of course use the RS ( Prelog) system to describe the configuration of one or more of the asymmetric carbon atoms

7

Even though the RS system is widely accepted today as a standard for designating configuration the configuration of carbohydrates as well as those of amino acids and many other compounds in biochemistry is commonly designated by the DL system proposed by Emil Fischer in 1891

8

CHO

CH OH

CH2OH

CHO

C HHO

CH2OH

(R)-Glyceraldehyde (S)-Glyceraldehyde

4 C 3

1

2

4 C 2

1

3

(S) (R)

The DL is ( Rosanoff) systemDextrorotatory (+) If sugar solution turns the plane of polarized light to rightLevorotatory (ndash) If the sugar solution turns the plane of polarized light to leftRacemic mixture Equimolar mixture of optical isomers has no net rotation

1 Monosaccharides contain one or more asymmetric C-atoms get D- and L-forms where D- and L- designate absolute configuration

2 D-form -OH group is attached to the right of the asymmetric carbon3 L-form -OH group is attached to the left of the asymmetric carbon4 If there is more than one chiral C-atom absolute configuration of chiral C

furthest away from carbonyl group determines whether D- or L-

Optical activityD and L

configurations

examples of chiral Carbon atoms

Highest numbered streocente

r

The aldo hexoses have four asymmetric carbons and therefore exist as 16 possible stereo isomers

11

HOH2C

OH

HC

OH

HC

OH

HC

HC

OH

CH

O

Aldohexosesfour asymmetric carbons

24 = 16 stereoisomers

1 2 3 4

Diastereomers Each diastereomer is a different carbohydrate with different properties

known by a different name

Each of the monosaccharides has an enantiomer For example the two enantiomers of glucose have the following structures

12

HC

OHH

HHO

OHH

OHH

CH2OH

HC

HO H

H OH

HO H

HO H

CH2OH

O

Enantiomers of glucose

D - L -

O

EPIMERISMSugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)

Chemists commonly use two-dimensional representations called Fischer projections to show the configuration of carbohydrates

A Fischer projection is used to differentiate between L- and D- molecules On a Fischer projection the penultimate carbon of D sugars are depicted with hydrogen on the left and hydroxyl on the right L sugars will be shown with the hydrogen on the right and the hydroxyl on the left

Fischer Projection Formulas(ACyclic Form of Carbohydrate)

The Fischer projection devised by Hermann Emil Fischer in 1891 is a two-dimensional representation of a three-

dimensional organic molecule by projection15

The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center

16

Paper plane

When relating one Fischer projection to another its important to realise that it may only be manipulated within the 2D plane in which it is drawn (that is it may not be rotated within 3D space) and even then it can only rotated in the plane it is drawn (2D) by 180o

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Even though the RS system is widely accepted today as a standard for designating configuration the configuration of carbohydrates as well as those of amino acids and many other compounds in biochemistry is commonly designated by the DL system proposed by Emil Fischer in 1891

8

CHO

CH OH

CH2OH

CHO

C HHO

CH2OH

(R)-Glyceraldehyde (S)-Glyceraldehyde

4 C 3

1

2

4 C 2

1

3

(S) (R)

The DL is ( Rosanoff) systemDextrorotatory (+) If sugar solution turns the plane of polarized light to rightLevorotatory (ndash) If the sugar solution turns the plane of polarized light to leftRacemic mixture Equimolar mixture of optical isomers has no net rotation

1 Monosaccharides contain one or more asymmetric C-atoms get D- and L-forms where D- and L- designate absolute configuration

2 D-form -OH group is attached to the right of the asymmetric carbon3 L-form -OH group is attached to the left of the asymmetric carbon4 If there is more than one chiral C-atom absolute configuration of chiral C

furthest away from carbonyl group determines whether D- or L-

Optical activityD and L

configurations

examples of chiral Carbon atoms

Highest numbered streocente

r

The aldo hexoses have four asymmetric carbons and therefore exist as 16 possible stereo isomers

11

HOH2C

OH

HC

OH

HC

OH

HC

HC

OH

CH

O

Aldohexosesfour asymmetric carbons

24 = 16 stereoisomers

1 2 3 4

Diastereomers Each diastereomer is a different carbohydrate with different properties

known by a different name

Each of the monosaccharides has an enantiomer For example the two enantiomers of glucose have the following structures

12

HC

OHH

HHO

OHH

OHH

CH2OH

HC

HO H

H OH

HO H

HO H

CH2OH

O

Enantiomers of glucose

D - L -

O

EPIMERISMSugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)

Chemists commonly use two-dimensional representations called Fischer projections to show the configuration of carbohydrates

A Fischer projection is used to differentiate between L- and D- molecules On a Fischer projection the penultimate carbon of D sugars are depicted with hydrogen on the left and hydroxyl on the right L sugars will be shown with the hydrogen on the right and the hydroxyl on the left

Fischer Projection Formulas(ACyclic Form of Carbohydrate)

The Fischer projection devised by Hermann Emil Fischer in 1891 is a two-dimensional representation of a three-

dimensional organic molecule by projection15

The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center

16

Paper plane

When relating one Fischer projection to another its important to realise that it may only be manipulated within the 2D plane in which it is drawn (that is it may not be rotated within 3D space) and even then it can only rotated in the plane it is drawn (2D) by 180o

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

The DL is ( Rosanoff) systemDextrorotatory (+) If sugar solution turns the plane of polarized light to rightLevorotatory (ndash) If the sugar solution turns the plane of polarized light to leftRacemic mixture Equimolar mixture of optical isomers has no net rotation

1 Monosaccharides contain one or more asymmetric C-atoms get D- and L-forms where D- and L- designate absolute configuration

2 D-form -OH group is attached to the right of the asymmetric carbon3 L-form -OH group is attached to the left of the asymmetric carbon4 If there is more than one chiral C-atom absolute configuration of chiral C

furthest away from carbonyl group determines whether D- or L-

Optical activityD and L

configurations

examples of chiral Carbon atoms

Highest numbered streocente

r

The aldo hexoses have four asymmetric carbons and therefore exist as 16 possible stereo isomers

11

HOH2C

OH

HC

OH

HC

OH

HC

HC

OH

CH

O

Aldohexosesfour asymmetric carbons

24 = 16 stereoisomers

1 2 3 4

Diastereomers Each diastereomer is a different carbohydrate with different properties

known by a different name

Each of the monosaccharides has an enantiomer For example the two enantiomers of glucose have the following structures

12

HC

OHH

HHO

OHH

OHH

CH2OH

HC

HO H

H OH

HO H

HO H

CH2OH

O

Enantiomers of glucose

D - L -

O

EPIMERISMSugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)

Chemists commonly use two-dimensional representations called Fischer projections to show the configuration of carbohydrates

A Fischer projection is used to differentiate between L- and D- molecules On a Fischer projection the penultimate carbon of D sugars are depicted with hydrogen on the left and hydroxyl on the right L sugars will be shown with the hydrogen on the right and the hydroxyl on the left

Fischer Projection Formulas(ACyclic Form of Carbohydrate)

The Fischer projection devised by Hermann Emil Fischer in 1891 is a two-dimensional representation of a three-

dimensional organic molecule by projection15

The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center

16

Paper plane

When relating one Fischer projection to another its important to realise that it may only be manipulated within the 2D plane in which it is drawn (that is it may not be rotated within 3D space) and even then it can only rotated in the plane it is drawn (2D) by 180o

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

examples of chiral Carbon atoms

Highest numbered streocente

r

The aldo hexoses have four asymmetric carbons and therefore exist as 16 possible stereo isomers

11

HOH2C

OH

HC

OH

HC

OH

HC

HC

OH

CH

O

Aldohexosesfour asymmetric carbons

24 = 16 stereoisomers

1 2 3 4

Diastereomers Each diastereomer is a different carbohydrate with different properties

known by a different name

Each of the monosaccharides has an enantiomer For example the two enantiomers of glucose have the following structures

12

HC

OHH

HHO

OHH

OHH

CH2OH

HC

HO H

H OH

HO H

HO H

CH2OH

O

Enantiomers of glucose

D - L -

O

EPIMERISMSugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)

Chemists commonly use two-dimensional representations called Fischer projections to show the configuration of carbohydrates

A Fischer projection is used to differentiate between L- and D- molecules On a Fischer projection the penultimate carbon of D sugars are depicted with hydrogen on the left and hydroxyl on the right L sugars will be shown with the hydrogen on the right and the hydroxyl on the left

Fischer Projection Formulas(ACyclic Form of Carbohydrate)

The Fischer projection devised by Hermann Emil Fischer in 1891 is a two-dimensional representation of a three-

dimensional organic molecule by projection15

The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center

16

Paper plane

When relating one Fischer projection to another its important to realise that it may only be manipulated within the 2D plane in which it is drawn (that is it may not be rotated within 3D space) and even then it can only rotated in the plane it is drawn (2D) by 180o

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

The aldo hexoses have four asymmetric carbons and therefore exist as 16 possible stereo isomers

11

HOH2C

OH

HC

OH

HC

OH

HC

HC

OH

CH

O

Aldohexosesfour asymmetric carbons

24 = 16 stereoisomers

1 2 3 4

Diastereomers Each diastereomer is a different carbohydrate with different properties

known by a different name

Each of the monosaccharides has an enantiomer For example the two enantiomers of glucose have the following structures

12

HC

OHH

HHO

OHH

OHH

CH2OH

HC

HO H

H OH

HO H

HO H

CH2OH

O

Enantiomers of glucose

D - L -

O

EPIMERISMSugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)

Chemists commonly use two-dimensional representations called Fischer projections to show the configuration of carbohydrates

A Fischer projection is used to differentiate between L- and D- molecules On a Fischer projection the penultimate carbon of D sugars are depicted with hydrogen on the left and hydroxyl on the right L sugars will be shown with the hydrogen on the right and the hydroxyl on the left

Fischer Projection Formulas(ACyclic Form of Carbohydrate)

The Fischer projection devised by Hermann Emil Fischer in 1891 is a two-dimensional representation of a three-

dimensional organic molecule by projection15

The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center

16

Paper plane

When relating one Fischer projection to another its important to realise that it may only be manipulated within the 2D plane in which it is drawn (that is it may not be rotated within 3D space) and even then it can only rotated in the plane it is drawn (2D) by 180o

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Diastereomers Each diastereomer is a different carbohydrate with different properties

known by a different name

Each of the monosaccharides has an enantiomer For example the two enantiomers of glucose have the following structures

12

HC

OHH

HHO

OHH

OHH

CH2OH

HC

HO H

H OH

HO H

HO H

CH2OH

O

Enantiomers of glucose

D - L -

O

EPIMERISMSugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)

Chemists commonly use two-dimensional representations called Fischer projections to show the configuration of carbohydrates

A Fischer projection is used to differentiate between L- and D- molecules On a Fischer projection the penultimate carbon of D sugars are depicted with hydrogen on the left and hydroxyl on the right L sugars will be shown with the hydrogen on the right and the hydroxyl on the left

Fischer Projection Formulas(ACyclic Form of Carbohydrate)

The Fischer projection devised by Hermann Emil Fischer in 1891 is a two-dimensional representation of a three-

dimensional organic molecule by projection15

The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center

16

Paper plane

When relating one Fischer projection to another its important to realise that it may only be manipulated within the 2D plane in which it is drawn (that is it may not be rotated within 3D space) and even then it can only rotated in the plane it is drawn (2D) by 180o

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

EPIMERISMSugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)

Chemists commonly use two-dimensional representations called Fischer projections to show the configuration of carbohydrates

A Fischer projection is used to differentiate between L- and D- molecules On a Fischer projection the penultimate carbon of D sugars are depicted with hydrogen on the left and hydroxyl on the right L sugars will be shown with the hydrogen on the right and the hydroxyl on the left

Fischer Projection Formulas(ACyclic Form of Carbohydrate)

The Fischer projection devised by Hermann Emil Fischer in 1891 is a two-dimensional representation of a three-

dimensional organic molecule by projection15

The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center

16

Paper plane

When relating one Fischer projection to another its important to realise that it may only be manipulated within the 2D plane in which it is drawn (that is it may not be rotated within 3D space) and even then it can only rotated in the plane it is drawn (2D) by 180o

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Chemists commonly use two-dimensional representations called Fischer projections to show the configuration of carbohydrates

A Fischer projection is used to differentiate between L- and D- molecules On a Fischer projection the penultimate carbon of D sugars are depicted with hydrogen on the left and hydroxyl on the right L sugars will be shown with the hydrogen on the right and the hydroxyl on the left

Fischer Projection Formulas(ACyclic Form of Carbohydrate)

The Fischer projection devised by Hermann Emil Fischer in 1891 is a two-dimensional representation of a three-

dimensional organic molecule by projection15

The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center

16

Paper plane

When relating one Fischer projection to another its important to realise that it may only be manipulated within the 2D plane in which it is drawn (that is it may not be rotated within 3D space) and even then it can only rotated in the plane it is drawn (2D) by 180o

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Fischer Projection Formulas(ACyclic Form of Carbohydrate)

The Fischer projection devised by Hermann Emil Fischer in 1891 is a two-dimensional representation of a three-

dimensional organic molecule by projection15

The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center

16

Paper plane

When relating one Fischer projection to another its important to realise that it may only be manipulated within the 2D plane in which it is drawn (that is it may not be rotated within 3D space) and even then it can only rotated in the plane it is drawn (2D) by 180o

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center

16

Paper plane

When relating one Fischer projection to another its important to realise that it may only be manipulated within the 2D plane in which it is drawn (that is it may not be rotated within 3D space) and even then it can only rotated in the plane it is drawn (2D) by 180o

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

When relating one Fischer projection to another its important to realise that it may only be manipulated within the 2D plane in which it is drawn (that is it may not be rotated within 3D space) and even then it can only rotated in the plane it is drawn (2D) by 180o

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Why cant you rotate it 270o or 90o A 90o rotation is equivalent to breaking bonds

and exchanging two groups which would result in the formation of the other enantiomer

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Fischer proposed that these enantiomers be designated D and L (for dextro and levorotatory) but he had no experimental way to determine which enantiomer has which specific rotation

He assigned the dextrorotatory enantiomer an arbitrary configuration and named it D-glyceraldehyde He named its enantiomer L-glyceraldehyde

19

CHO

CH OH

CH2OH

D-Glyceraldehyde[]D = +135

CHO

C HHO

CH2OH

25L-Glyceraldehyde

[]D = -13525

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Fischer could have been wrong but it was proven in 1952 by a special application of X-ray crystallography

D- and L-glyceraldehyde serve as reference points for the assignment of relative configuration to all other aldoses and ketoses

The reference point is the chiral center farthest from the carbonyl group Because this chiral center is always the next to the last carbon on the chain it is called the penultimate carbon

A D-monosaccharide has the same configuration at its penultimate carbon as D-glyceraldehyde (its-OH is on the right when written as a Fischer projection) an L-monosaccharide has the same configuration at its penultimate carbon as L-glyceraldehyde

20

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

When creating a Fischer projection for a carbohydrate with more than three carbons each down carbon that would project away from you as viewed from the top in the Zig-Zag model must be turned around and oriented as towards your view However this does not alter the Fischer projections for any previous carbons

CHO

H OH

H OH

CH2OH

CHO

HO H

H OH

CH2OH

D-(-)-Erythrose D-(-)-Threose

CHO

H OH

H OH

H OH

CH2OHD-(-)-Ribose

H

OH

O

OH

H2C

HO

H

O

OH

H2C

HO

OH

H

OH

O

OH

CH2

OH

HO4

32

15

2(R)3(R)4(R)5-tetrahydroxypentanal

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Haworth Projection ( Cyclic Form)

Cyclization via intramolecular hemiacetal (hemiketal) formationC-1 becomes chiral upon cyclization - anomeric carbonAnomeric C contains -OH group which may be or mutarotation

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

The Haworth projection can be obtained from a Fischer projection in the following way

The C5 hydrogen exchange with the C5 hydroxymethyl group of α-D-glucopyranose written as Fischer projection will produce A

whereas the C5 hydrogen exchange with the C5 ring oxygen will produce B

Fischer A B Haworth

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Haworth Projection

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

A ketose Fructose

α

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

In the Fischer projection at the anomeric and the reference carbon atom is designated α In the α-anomer the exocyclic oxygen atom at the anomeric center is formally cis to the oxygen atom attached to the anomeric reference atom in the β anomer these oxygen atoms are formally trans

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

α

β

α

β

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Conformation of a molecule can be defined as a spatial arrangement of its atoms (or ligands) in a molecule that is obtained by free rotations about single bonds

The rotation of two methyl groups of ethane about the CndashC single bond should theoretically produce also an ldquoinfiniterdquo number of conformations if the rotation about the CndashC bond was completely free However due to a nonbonded interaction between the hydrogen atoms on two adjacent methyl groups torsional or Pitzer strain لم تكتمل وتراجع

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Conformation of monosaccharideOf

furanose form

Of pyranose

form

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Conformational Analysis of Cyclic (Lactol Hemiacetal)Forms of Monosaccharides

Furanose ring structures occur in envelope (E) and twist (T) conformations

As the difference in energy between the different conformations on the wheel is generally low two regions having low energy conformations occurring in the Northern and Southern can be identified

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

a pseudo-rotational wheel

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Six-membered ring structures can occur in two chair (C) six boat (B) six skew (S) and twelve

half-chair ( H) conformations In practice the two chair conformations have the

lowest energy and strongly dominate The preference for these low energy

conformations is dictated by the relative orientations of the hydroxyl groups In the case of D-glucopyranoses only the 4C1 conformation is of importance whereas the 1C4 conformation dominates in α-D-idopyranose

Cases occur as in β-D-arabinopyranose where both chair conformations are in equilibrium

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

3 Carbohydrat Classfication

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

There are three major size classes of carbohydrates

Monosaccharides carbohydrates that cannot be hydrolyzed to simpler

carbohydrates eg Glucose or fructose

Oligosaccharidescarbohydrates that can be hydrolyzed into a few (2-10)

monosaccharide units eg Sucrose or lactose

Polysaccharides carbohydrates that are yield larg number of monosaccharide eg

Starch or cellulose

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Monosaccharide

Classified according to (1)number of carbon atoms

(2) What they contain an aldehyde or keto group

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

The structure and classification of some monosaccharides

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

NomenclatureNumber of

carbonsFunctional group

Ketone Aldehyde

4 Ketotetrose aldotetrose

5 Ketopentose Aldopentose

6 Ketohexose Aldohexose

7 ketoheptose aldoheptose

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Reactions of MonosaccharidesI Isomerization reactionII Addition reaction of carbonyl groupIII Nucleophilic substitution reaction of the

anomeric carbonIV Reactions of the hydroxyl groupV Oxidation VI reduction

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

I Isomerization reactionA Mutarotation (anomerization)

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

B Epimerization

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Hydride transfer mechanism

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

II Addition reaction of carbonyl group

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

B Addition of nitroalkan

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

C Addition of diazomethan

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

D Wittig Reaction

Olefinic sugar

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

E Condensation with NN-disubstituted hydrazine

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

F Condensation with hydrazine

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

G Condensation with aryl hydrazine ( osazone formation)

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Due to the chelated structure of osazone

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Saccharide arylosazone undergo some important reactions

1- Oxidative cyclization

2- Reductive elimenation

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

H Condensation with hydroxyl amine

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

III Nucleophilic substitution reaction of the anomeric carbonThe two main reactions are(a) glycosidation(b) glycosyl halide formation

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

A Glycosidation A leaving group (OH OCOR X) at the anomeric

carbon is displaced by an alkoxy (OR) or aryloxy (OAr) to give glycofuranoside or glycopyranoside

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

1- Fischer glycosidation

Methyl glycoside

More stable

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

2- Helferich glycosidation Helferich glycosylation reaction has been

used to synthesize O-glycosides from protected glycosyl bromide and alcohol (or another carbohydrate) in the presence of mercuric cyanide It is also referred to as the Helferich condition This reaction involves the SN2 substitution mechanism leads the formation of β-glycoside and release of HgCNBr This reaction has been used in the preparation of glycosides

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

3- Koenigs-Knorr glycosidation is the substitution reaction of a glycosyl halide with

an alcohol to give a glycoside

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

B Glycoyl halide formation

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

GLYCOSIDE FORMATIONThe hydroxyl group of anomeric carbon of a

carbohydrate can join with a hydroxyl group of another

carbohydrate or some other compound to form a

glycoside and the bond so formed is known as glycosidic

bond

eg R-OH + HO-R 1048774R-O-R + H2O

The non-carbohydrate moiety is known as aglycone ndash

phenol sterol bases CH3OH glycerol

Glycosidic bond can be N-linked or O-linked

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

IV Reactions of the hydroxyl group

RCOORrsquo RORrsquo

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

1 Ester formation

Benzoyl chloride

Benzoate ester

Acetate ester

1- acetate ester

2- benzoate ester

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Sulfonate ester

Intramolecular displacement

transαβ-anhydro sugar

(epoxy)

3- sulphonate ester

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Displacement with OH-

Displacement with RCOO-

cis

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

4- phosphate ester

5- sulfate ester

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

2 Ether formation

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

3 Cyclic acetal and ketal formation

RR

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

V Oxidation and reduction Oxidation Reduction To aldonic by Br2 NaBH4

To aldaric by HNO3 LiAlH4

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

AMINO SUGARSAmino groups are substituted for hydroxy groups of sugars

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

DEOXY SUGARSOxygen of the hydroxyl group is removed

to form deoxy sugarsNon reducing and non osazone formingimportant part of nucleic acids

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

OligosaccharidesComposed of a few monosaccharide units by glycosidic

link from C-1 of one unit and -OH of second unit13 14 1 6 links most common but 1 1 and 1 2

are possibleLinks may be or Link around glycosidic bond is fixed but anomeric

forms on the other C-1 are still in equilibrium

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Disaccharidesbull Three main disaccharides sucrose maltose

lactose

bull All are isomers with molecular formula C12H22O11

bull On hydrolysis they yield 2 monosaccharidebull which soluble in waterbull Even though they are soluble in water they are

too large to pass through the cell membrane

76

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Disaccharides

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Sucrosecane sugarWhen hydrolyzed it forms a mixture of glucose

and fructoseDehydration synthesis of a sucrose molecule

formed from condensation of a glucose with a fructose

78

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Formation of sucrose

79

α β

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Maltose malt sugarPresent in germinating grainProduced commercially by hydrolysis of

starch

80

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Formation of maltose

81

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Lactoseknown as milk sugarBacteria cause fermentation of lactose

forming lactic acidWhen these reaction occur it changes the

taste to a sour one

82

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Formation of lactose

83

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Higher Oligosaccharides

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Polysaccharides

Polysaccharide Animationmp4

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Polysaccharides are large molecules containing 10 or more monosaccharide units

Polysaccharides are complex carbohydrates made uplinked monosaccharide units

monosaccharides or their derivatives held together by glycosidic bonds

Sources of PolysaccharidesMicrobial fermentationHigher plants

87

Polysaccharides

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

PolySaccharid

es

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Polysaccharid

es

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Storage Polysaccharides

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

1StarchStarch is a storage compound in

plants and made of glucose unitsIt is a homopolysaccharide made up

of two components amylose and amylopectin

Most starch is 10-30 amylose and 70-90 amylopectin

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Amylose and amylopectinmdashstarch

Starch is a mixture of amylose and amylopectin and is found in plant foods

Amylose makes up 20 of plant starch and is made up of 250ndash4000 D-glucose units bonded α(1rarr4) in a continuous chain

Long chains of amylose tend to coilAmylopectin makes up 80 of plant starch and is

made up of D-glucose units connected by α(1rarr4) glycosidic bonds

93

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

2 Amylose a straight chain structure formed by 14 glycosidic bonds

between α-D-glucose molecules

H O

OHH

OHH

OH

CH 2 OH

HO H

H

OHH

OH

CH 2 OH

H

O

HH H O

OH

OHH

OH

CH 2 OH

HH H O

H

OHH

OH

CH 2 OH

H

OH

HH O

OH

OHH

OH

CH 2 OH

H

O

H1

6

5

4

3

1

2

a m y lo s e

Structure of Amylose Fraction of Starch

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

bull The amylose chain forms a helix

bull This causes the blue colour change on reaction with iodine

bull Amylose is poorly soluble in water but forms micellar suspensions

Amylose

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Amylopectin causes a red-violet colour change on reaction with iodine

This change is usually masked by the much darker reaction of amylose to iodine Amylopectin

3 Amylopectin

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Amylopectin-a glucose polymer with mainly α -(14) linkages but it also has branches formed by α -(16) linkages Branches are generally longer than shown above

H O

OHH

OHH

OH

CH2OH

HO H

H

OHH

OH

CH2OH

H

O

HH H O

OH

OHH

OH

CH2

HH H O

H

OHH

OH

CH2OH

H

OH

HH O

OH

OHH

OH

CH2OH

H

O

H

O

1 4

6

H O

H

OHH

OH

CH2OH

HH H O

H

OHH

OH

CH2OH

HH

O1

OH

3

4

5

2

amylopectin

Structure of Amylopectin Fraction of Starch

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Starch therefore consists of amylose helices entangled on branches of amylopectin

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

4 Glycogen

Storage polysaccharide in animalsGlycogen constitutes up to 10 of liver mass and 1-2 of muscle

mass Glycogen is stored energy for the organism Similar in structure to amylopectin only difference from starch

number of branches Alpha(16) branches every 8-12 residues Like amylopectin glycogen gives a red-violet color with iodine

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Glycogen is a storage polysaccharide found in animals

Glycogen is stored in the liver and muscles

Its structure is identical to amylopectin except that α(1rarr6) branching occurs about every 12 glucose units

When glucose is needed glycogen is hydrolyzed in the liver to glucose

100

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

glycogen

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Structural Polysaccharides

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

CelluloseCellulose contains glucose units bonded (1rarr4)

This glycosidic bond configuration changes the three-dimensional shape of cellulose compared with that of amylose

The chain of glucose units is straight This allows chains to align next to each other to form a strong rigid structure

104

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

The β-glucose molecules are joined by condensation ie the removal of water forming β-(14) glycosidic linkages

Note however that every second β -glucose molecule has to flip over to allow the bond to form This produces a ldquoheads-tails-headsrdquo sequence

The glucose units are linked into straight chains each 100-1000 units long

Weak hydrogen bonds form between parallel chains binding them into cellulose microfibrils

Cellulose microfibrils arrange themselves into thicker bundles called microfibrils (These are usually referred to as fibres)

The cellulose fibres are often ldquogluedrdquo together by other compounds such as hemicelluloses and calcium pectate to form complex structures such as plant cell walls

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Cellulose is an insoluble fiber in our diet because we lack the enzyme cellulase to hydrolyze the (1rarr4) glycosidic bond

Whole grains are a good source of cellulose

Cellulose is important in our diet because it assists with digestive movement in the small and large intestine

Some animals and insects can digest cellulose because they contain bacteria that produce cellulase 106

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

107

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

2 pectin

Cell wall polysaccharide

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

bull Source Cell walls of higher plants (citrus rind)bull Structure Largely a linear polymer of polygalacturonic acid with

varying degrees of methyl esterification (Also some branches ndashHAIRY REGIONS)ndash gt50 esterified is a high methoxy (HM) pectin ndash lt50 esterified is a low methoxy (LM) pectin

bull Functional Properties Main use as gelling agent (jams jellies)

ndash dependent on degree of methylationndash high methoxyl pectins gel through H-bonding and in presence of sugar

and acidndash low methoxyl pectins gel in the presence of Ca2+

Thickeners Water binders Stabilizers

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Pectin Model

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

3 ChitinChitin makes up the exoskeleton of insects and

crustaceans and cell walls of some fungiIt is made up of N-acetyl glucosamine

containing (1rarr4) glycosidic bondsIt is structurally strongChitin is used as surgical thread that

biodegrades as a wound healsIt serves as a protection from water in insectsChitin is also used to waterproof paper and in

cosmetics and lotions to retain moisture113

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

114

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

4Heparin

Heparin is a medically important polysaccharide because it prevents clotting in the bloodstream

115

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

It is a highly ionic polysaccharide of repeating disaccharide units of an oxidized monosaccharide and D-glucosamine Heparin also contains sulfate groups that are negatively charged

It belongs to a group of polysaccharides called glycosaminoglycans

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

5- chitosanSource Crustacean shells insect exoskeleton and

some fungi = mainly chitinβ(1 4) linked D-glucos-2-amine units

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

119

ChitinChitosan

Deacetylation(boiling 40-50NaOH)

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

120

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Other polysaccharidesOther polysaccharides

bull CalloseCallose (poly 1-3 glucose) found in the walls (poly 1-3 glucose) found in the walls of phloem tubesof phloem tubes

bull Dextran Dextran (poly 1-2 1-3 and 1-4 glucose) the (poly 1-2 1-3 and 1-4 glucose) the storage polysaccharide in fungi and bacteriastorage polysaccharide in fungi and bacteria

bull InulinInulin (poly fructose) a plant food store (poly fructose) a plant food store

bull AgarAgar (poly galactose sulphate) found in (poly galactose sulphate) found in algae and used to make agar platesalgae and used to make agar plates

bull MureinMurein (a sugar-peptide polymer) found in (a sugar-peptide polymer) found in bacterial cell wallsbacterial cell walls

bull LigninLignin (a complex polymer) found in the (a complex polymer) found in the walls of xylem cells is the main component walls of xylem cells is the main component of woodof wood

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

(a) Flat ribbon type conformation Cellulose

(b) Buckled ribbon type conformation Alginate

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

2- Hollow helix type structures

Tight helix - void can be filled by including molecules of appropriate size and shape

More extended helix - two or three chains may twist around each other to form double or triple helix

Very extended helix - chains can nest ie close pack without twisting around each other

amylose-iodine helix

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Amylose forms inclusion complexes with iodine phenoln-butanol etc

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Conformation Zones

Zone A Extra-rigid rod schizophyllan

Zone B Rigid Rod xanthan

Zone C Semi-flexible coil pectin

Zone D Random coil dextran pullulan

Zone E Highly branched amylopectin glycogen

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

PROTEOGLYCANS amp GLYCOPROTEINSProteoglycans When carbohydrate chains

are attached to a polypeptide chain

Glycoproteins Carbohydrate content le 10

Mucoprotein Carbohydrate content ge10

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Four levels of Protein Structure(a) The primary structure is the succession of amino acid residues usually abbreviated by the 1- or 3-letter codes

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

(b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

(c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

(d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits

In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

The Four Levels of Protein Structuremp4

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Monosaccharide component The polysaccharide samples are hydrolyzed by HClMeOH and TFA then analyzed by HPLC or GC

HPLC

High pressureperformance liquid chromatography

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Sugar linkage type Chemical methods Periodate Oxidation and Smith degradation Methylation analysis

GC-MSGas chromatography-Mass spectrometer

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Physical methods

NMR(Nuclear Magnetic Resonance)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branching

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Physical methods FT-IR (Fourier transform infrared spectroscopy)

bull Monosaccharide configurationbull Substitute units

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

Physical methods MS (Mass spectrometer)

bull Sugar linkage typebull Monosaccharide configurationbull Substitute units bull Degree of branchingbull Molecular weight

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139

• Carbohydrates and Polysaccharides
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• EPIMERISM Sugars are different from one another only in configuration with regard to a single C atom (other than the reference C atom)
• Slide 14
• Fischer Projection Formulas (ACyclic Form of Carbohydrate)
• The horizontal segments of a Fischer projection represent bonds directed toward the viewer (coming out of the plane of the paper) and the vertical segments represent bonds directed away from the viewer (going behind the plane of the paper) The only atom in the plane of the paper is the chiral center
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• Slide 21
• Haworth Projection ( Cyclic Form)
• Slide 23
• Slide 24
• Slide 25
• Slide 26
• Slide 27
• Slide 28
• Slide 29
• Conformation of monosaccharide
• Slide 31
• Slide 32
• Slide 33
• Slide 34
• 3 Carbohydrat Classfication
• Slide 36
• Monosaccharide
• Slide 38
• Nomenclature
• Reactions of Monosaccharides
• I Isomerization reaction
• B Epimerization
• Hydride transfer mechanism
• II Addition reaction of carbonyl group
• B Addition of nitroalkan
• C Addition of diazomethan
• D Wittig Reaction
• E Condensation with NN-disubstituted hydrazine
• F Condensation with hydrazine
• G Condensation with aryl hydrazine ( osazone formation)
• Slide 51
• Saccharide arylosazone undergo some important reactions
• H Condensation with hydroxyl amine
• III Nucleophilic substitution reaction of the anomeric carbon
• Slide 55
• Slide 56
• Slide 57
• 3- Koenigs-Knorr glycosidation
• B Glycoyl halide formation
• GLYCOSIDE FORMATION
• Slide 61
• IV Reactions of the hydroxyl group
• 1 Ester formation
• Slide 64
• Slide 65
• 4- phosphate ester
• 2 Ether formation
• Slide 68
• Slide 69
• 3 Cyclic acetal and ketal formation
• Slide 71
• V Oxidation and reduction
• AMINO SUGARS Amino groups are substituted for hydroxy groups of sugars
• DEOXY SUGARS
• Oligosaccharides
• Disaccharides
• Slide 77
• Sucrose
• Formation of sucrose
• Maltose
• Formation of maltose
• Lactose
• Formation of lactose
• Slide 84
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• Slide 89
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• 1Cellulose
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• Slide 113
• Slide 114
• Slide 115
• Slide 116
• The major repeating unit is the trisulfated disaccharide 2-O-sulfo-α-L-iduronic acid 14 linked to 6-O-sulfo-N-sulfo-α-D-glucosamine (4]IdoA2S(14)GlcNS6S[1)
• 5- chitosan
• Physico-chemical properties
• Reactivity
• Slide 121
• Slide 122
• 1- Ribbon type structures
• 2- Hollow helix type structures
• Slide 125
• Examples of a single helix (cellulose) a double helix (amylose) and a triple helix (β-1rarr3-glucan)
• Slide 127
• PROTEOGLYCANS amp GLYCOPROTEINS
• Slide 129
• (b) The secondary structure is the 3-D arrangement of the right-handed alpha helix or alternative structures such as a beta-pleated sheet
• (c) The tertiary structure is the 3-D folding of the alpha helix (show as a purple ribbon) shaped by structures such as proline corners disulfide bridges between cysteine residues and electrostic bonds
• (d) Where more than one protein chain contributes to the protein the quaternary structure is the arrangement of these subunits In hemoglobin as shown here the quaternary structure comprises two alpha and two beta polypeptides held together by elecrostatic bonds
• Slide 133
• Slide 134
• Slide 135
• Slide 136
• Slide 137
• Slide 138
• Slide 139