enzymes powerpoint

7/27/2019 Enzymes Powerpoint

1/39

ENZYMES

STRUCTURE

AFFECTING FACTORS

MECHANISM


2/39

Cofactor

Apoenzyme/

apoprotein Prostetic Group

Coenzyme

Holoenzyme

ENZYME STRUCTURE


3/39

Cofactor: komponen non protein

untuk membantu aktivitas enzim

(beberapa berupa ion anorganik) Kofaktor berupa ion organik disebut

coenzym

Apoenzyme or apoprotein: Enzim ygmemerlukan kofaktor tetapi tidak

memilikinya.(Enzim tanpa kofaktor)

Hanya tersusun dari protein,Ex.Pepsin

Simple enzym.


4/39

Molekul non-protein

ygdiikat enzim untukmelakukanfungsinya. ex,.katalase

PROSTETIC GROUP


5/39

Prostetics Group

COFACTORS COENZYMES

Such as the metalions Mg2+, Cu+, Mn2+or iron-sulfur clustersInorganic

Senyawa organikContoh: NADH

Dilepaskan dari sisiaktif saat bereaksi


6/39

Space-filling model of the coenzyme

NADH

Coenzymes aresmall organic

molecules thattransport chemicalgroups from one

enzyme to another
http://en.wikipedia.org/wiki/File:NADH-3D-vdW.png


7/39

Holoenzyme

Apoenzim yangdilengkapi

kofaktornya

Merupakan enzim

dalam keadaanaktif.


8/39

The active site Is the region on the enzyme where thesubstrate binds

Figure 8.16

Substate

Active site

Enzyme

(a)


9/39

Karakteristik sisi aktifenzim

Merupakan bagian kecil dari enzim

Sisi aktif merupakan suatu cekukan yangbersifat 3 dimensi. memberikan

lingkungan mikro yg sesuai untuk terjadinyasuatu reaksi kimia

substrat terikat pada sisi aktif denganinteraksi / ikatan yang lemah.

Spesifitas enzim dipengaruhi oleh asamamino yg menyusun sisi aktif suatu enzim


10/39

TEORI CARA KERJA ENZIM

Induced Fit theory

Lock and Key theory


11/39

Induced fit of a substrate Brings chemical groups of the active site

into positions that enhance their ability tocatalyze the chemical reaction

Figure 8.16 (b)

Enzyme- substratecomplex


12/39

Induced Fit theory

Sisi aktif mengubah konformasi(bentuknya) agar cocok dengan bentuksubstratnya.

Mempertimbangkan fleksibilitas protein


13/39

Induced Fit Theory


14/39

"the Lock and Key" Model

Both the enzymeand the substratepossess specificcomplementarygeometric shapesthat fit exactly into

one andother.(Bentuk sisiaktif enzim pas dgbentuk substrat.)


15/39

The catalytic cycle of an enzyme

Substrates

Products

Enzyme

Enzyme-substratecomplex

1 Substrates enter active site; enzymechanges shape so its active siteembraces the substrates (induced fit).

2 Substrates held inactive site by weakinteractions, such ashydrogen bonds andionic bonds.

3 Active site (and R groups of

its amino acids) can lower EAand speed up a reaction by acting as a template for

substrate orientation, stressing the substrates

and stabilizing thetransition state,

providing a favorablemicroenvironment,

participating directly in thecatalytic reaction.

4 Substrates areConverted intoProducts.

5 Products areReleased.

6 Active siteIs available fortwo new substrateMole.

Figure 8.17


16/39

Faktor-Faktor yg mempengaruhi kerjaEnzim (riyandhanu,haris,rahnata)

Konsentrasi Enzim

Konsentrasi Substrat

Suhu

pH

Konsentrasi air

Inhibitor

Aktivator


17/39

Konsentrasi Enzim

Kecepatan reaksi dipengaruhi olehkonsentrasi enzim, makin besarkonsentrasi enzim makin tinggi pula

kecepatan reaksi

Konsentrasi enzim berbanding lurus

dengan kecepatan reaksi


18/39

Concentration of Enzyme


19/39

Concentration of Substrate

Peningkatan konsentransi substratdapat meningkatkan kecepatan reaksi

bila jumlah enzim tetap. Namun pada

saat sisi aktif semua enzim berikatandengan substrat, penambahan

substrat tidak dapat meningkatkan

kecepatan reaksi enzim selanjutnya.


20/39

Concentration of Substrate


21/39

Effects of Temperature and

pH

Each enzyme

Has an optimal temperature in which it canfunction

Figure 8.18

Optimal temperature forenzyme of thermophilic

Rate

ofreaction

0 20 40 80 100Temperature (C)

(a) Optimal temperature for two enzymes

Optimal temperature fortypical human enzyme

(heat-tolerant)bacteria


22/39

Pengaruh Suhu pada aktivitas Enzim

Umumnya, Enzim akan terdenaturasipada suhu yang terlalu tinggi.

Pada suhu yg terlalu rendah enzim

umumnya akan menjadi inaktif tetapidapat kembali aktif apabila suhu

normal kembali.


23/39

Has an optimal pH in which it can function

Figure 8.18

Rate

ofr

eaction

(b) Optimal pH for two enzymes

Optimal pH for pepsin(stomach enzyme)

Optimal pHfor trypsin(intestinalenzyme)

10 2 3 4 5 6 7 8 9


24/39

Gerry, aryo, hafiz: ATP

(pengertian,struktur, fungsi dalam

metabolisme)Adi,azhar,rafif: metabolic reaction

(hydrolysis,condensation,)

Rilo,tegar,novrian: Oxidasi-Reduction

Ihsan,pinayungan,vlady:

Transphosphorylation Bagus,thareq,raka : Coenzym

Nadzir,ghazali,iqbal: other metabolic

reaction (salah satunya:


25/39

Azka dewa, dhito,kharist: ATP

(pengertian,struktur, fungsi dalam

metabolisme)

Insan, reynaldy,roni: metabolic

reaction (hydrolysis,condensation,)

Refta, barkah, alfin: metabolic

reaction (Oxidasi-Reduction)

Ivan, frans,Faiz: metabolic reaction

(Transphosphorylation)

Novan,Alan, Reyshaldy: Coenzym

Parama, Shiosi, Azka Hanif: other

metabolic reaction (salah satunya:

E


26/39

Enzyme

Inhibitors Competitive inhibitors

Bind to the active site of an enzyme, competingwith the substrate

Figure 8.19 (b) Competitive inhibition

A competitiveinhibitor mimics the

substrate, competingfor the active site.

Competitiveinhibitor

A substrate canbind normally to the

active site of anenzyme.

Substrate

Active site

Enzyme

(a) Normal binding


27/39

INHIBITOR KOMPETITIF

Molekul penghambat yang strukturnyamirip substrat, sehingga molekultersebut berkompetisi dengan substratuntuk bergabung pada sisi aktif enzim.

Contoh : sianida bersaing dengan oksigenuntuk mendapatkan Hemoglobin padarantai akhir respirasi.

Inhibitor kompetititf dapat diatasidengan penambahan konsentrasisubstrat.


28/39

Noncompetitive inhibitors Bind to another part of an enzyme,

changing the function

Figure 8.19

A noncompetitiveinhibitor binds to the

enzyme away fromthe active site, altering

the conformation ofthe enzyme so that its

active site no longerfunctions.

Noncompetitive inhibitor

(c) Noncompetitive inhibition


29/39

INHIBITOR NON KOMPETITIF

Molekul penghambat yang bekerjadengan cara melekatkan diri padabagian bukan sisi aktif enzim.

Inhibitor ini menyebabkan sisiaktif berubah sehingga tidakdapat berikatan dengan substrat.

Inhibitor nonkompetitif tidakdapat dipengaruhi oleh konsentrasisubstrat.


30/39

Aktivator Enzim

Molekul atau ion yang meningkatkanaktifitas enzim.

Yaitu: Kofaktor atau koenzim


31/39

ENRICHMENT

(PENGAYAAN)


32/39

Regulation of enzyme activity helpscontrol metabolism

A cells metabolic pathways

Must be tightly regulated


33/39

Allosteric Regulation of

Enzymes

Allosteric regulation

Is the term used to describe any case inwhich a proteins function at one site is

affected by binding of a regulatorymolecule at another site.

(Fungsi protein pada suatu situs yang

dipengaruhi oleh molekul yang terikat

pada situs lain)


34/39

Allosteric Activation and

Inhibition Many enzymes are allosterically

regulated


35/39

They change shape when regulatorymolecules bind to specific sites, affectingfunction

Stabilized inactiveform

Allosteric activaterstabilizes active fromAllosteric enyzme

with four subunitsActive site(one of four)

Regulatory

site (oneof four)

Active formActivator

Stabilized active form

Allosteric activaterstabilizes active form

InhibitorInactive formNon-functionalactivesite

(a) Allosteric activators and inhibitors. In the cell, activators and inhibitors

dissociate when at low concentrations. The enzyme can then oscillate again.

Oscillation

Figure 8.20

Cooperativity


36/39

Cooperativity

Is a form of allosteric regulation that canamplify enzyme activity (menguatkan

aktivitas enzim)

Figure 8.20

Binding of one substrate molecule toactive site of one subunit locksall subunits in active conformation.

Substrate

Inactive form Stabilized active form

(b)Cooperativity: another type of allosteric activation. Note that theinactive form shown on the left oscillates back and forth with the activeform when the active form is not stabilized by substrate.


37/39

Feedback Inhibition

In feedback inhibition

The end product of a metabolic pathwayshuts down the pathway


38/39

Feedback inhibition

Active siteavailable

Isoleucineused up bycell

Feedbackinhibition

Isoleucinebinds toallostericsite

Active site ofenzyme 1 nolonger bindsthreonine;pathway isswitched off

Initial substrate

(threonine)

Threoninein active site

Enzyme 1(threoninedeaminase)

Intermediate A

Intermediate B

Intermediate C

Intermediate D

Enzyme 2

Enzyme 3

Enzyme 4

Enzyme 5

End product

(isoleucine)

Figure 8.21


39/39

Thanks for your attention

enzymes powerpoint

Documents