Proteins

Made of C, H, O and N

Are a long polymer chains of Amino Acids (monomers)

The Amino Acids are bonded together at the Ribosome and then folded into a specific shape

- Each “shape” has a different function!

20 Different Amino Acids

Amino “Wing” Carboxyl Acid “Wing”

Amino Acids Make Proteins…

The Ribosome bonds the Amino Acids and they “Fold” into a correctly shaped protein!

Peptide bonds hold the Amino Acids together (so proteins are sometimes called polypeptides)

Proteins fold into correct shapes… to do the correct job!

Why Different Shapes?

Each Protein has a Specific Job…

There are proteins in muscle cells

There are proteins in hair follicles

There are protein hormones

- Dozens of different ones!

There are protein enzymes

- A “Bazillion” different ones!

- Why??? Because there are a “Bazillion” different chemical reactions going on!!!!

ENZYMESNEED A JOB

DONE?Call the trusted professionals at

ENZYME, Inc.

845-CAT-ALYST

Need a shed built? xSHED

Need a garage demolished? xRUBBLE

Need a toilet replaced? xPOTTY

How about fix a leaky roof? xLEAK

Need a job done?• How do things “change” in your body?

• Chemical Reactions• How are proteins built?

• Dehydration Synthesis• How are starches digested?

• Hydrolysis• What causes these Chemical Reactions?

• Enzymes! – Enzymes are CATALYSTS!

Enzymes

• Enzymes are a type of protein called catalysts

• Enzymes help all chemical reactions occur – A catalyst is a chemical that controls all

chemical reactions. • Enzymes control the rate of all chemical reactions!

Lock and Key• When you go home at night and

the door is locked, can it open itself? • Nope.

• Can you use your mom’s car key to open it?• No.

• You need a key that is just the right shape to fit in that lock. Otherwise, you're stuck in the cold. – And you had best start building

that igloo!!!

Specificity

• Enzymes work in a similar way (locks and keys).

• Enzymes complete very specific jobs and do nothing else.

• They are very specific “locks” and the compounds they work with are the special keys (they are called “substrates”). – Substrates are the raw materials needed to

make a product

Different Enzymes

– In the same way that there are door keys, car keys, and bike-lock keys, for every different door, car and bike lock…

– There are enzymes for every different reaction that has to occur in living things.–Sooo… there are thousands of

different, specific enzymes in every one of your cells!

So?

• The TYPE of chemical reactions that occur in cells depends on the TYPE of enzymes present in the cell!– Enzymes are SPECIFIC to each reaction

• And, Enzymes are Never Changed and they can be used over and over and over and … you get the idea!

Back to ENZYME, Inc…….

Call 888-CAT-ALYST

• When you need a job done, you call ENZYME, Inc.

• The “operator” decides which contractor to send to complete the job

Contractor• The contractor visits the site and finds the

raw materials• Reactants

• He begins working on the job assigned (he’s part of the “job” so he’s now the “enzyme substrate complex”)

• The raw materials are changed into a final product

• When he’s done… he walks away in search of another job.

Here’s the deal….

There are four steps in the process:

1. An enzyme and a substrate are present together. – Nothing can happen if they never meet each other! Hi,

I’m your fr

iend,

Enzyme.

Nice to meet you,

I’m Substra

te.

2. The enzyme bonds with the substrate at a special area called the active site. – The active site is a specially shaped area of

the enzyme that fits around the substrate. – The active site is the keyhole of the lock.

Enzyme-Substrate Complex

3. A “complex” made up of a substrate (raw materials) bound to the ACTIVE SITE of an enzyme is temporarily formed

The enzyme and substrate BIND together

– LETTER C

4. The enzyme completes it’s job and then lets go because it’s job is done! – Enzymes are never changed in the reaction.– Only the substrate (raw material) changes. – The substrate is now a product.

Which is the Enzyme-Substrate Complex?

A, B, or C

A

B

C

Can you stop them?• What if enzymes just kept

going and converted every molecule in the world?

• What if they never stopped... like some evil monster???

• Enzyme activity is regulated (and even stopped) by:– Temperature– pH levels

ACK! It’s the Evil

Enzyme Monster!

Activation Energy• Enzymes function by lowering the activation

energy of reactions.

Range B is the “activation energy” required to get the reaction “over the hump”…

The Rate of Chemical Reactions

• The rate (how fast or slow) of chemical reactions is directly controlled by the enzymes present.– And, if enzymes are affected by certain

factors, then…the chemical reaction rate is affected as well!

Enzyme Activity and Temp/pH• The activity of enzymes is affected by

changes in pH and temperature.

• Each enzyme works best at a certain pH (left

graph) and temperature (right graph), its activity decreases above and below that “optimum” point.

What does

optimum mean?

Why does this happen?

• Remember! Enzymes are PROTEINS

• Proteins are DENATURED by pH and Temperature extremes– Denaturing means “de”stroying the “natur”al

shape (the way the protein is folded)– If the protein unfolds, it loses it shape– If it loses its shape, it loses

its ability to function!• Structure and Function go

hand in hand!

Enzyme Names• Enzymes are named after the substrate

they can act upon• Plus, most of them end in “ase”!• For example:

– Protease breaks down protein

– Lipase breaks down lipids (fat)

– Amylase break down starches and other carbohydrates

• Amyl is Greek for starch!

– What do you think Cellulase breaks down?• Hint: humans lack this enzyme!

_______________

This is how it works…The

enzyme

can be

reused!

The enzyme is a biological catalyst!

An Example

Sucrose + H2O

Glucose + Fructose

Substrates

ProductsWhat do you think the name of this enzyme is???

Hint: It works on “Sucrose”!!!

Enzymes and Homeostasis

• Homeostasis is the maintenance of a constant (steady) internal balance.

• In living things, homeostasis shares a close relationship with enzyme function.

• Enzymes can destroy harmful substances that might disrupt homeostasis. – And homeostasis maintains conditions necessary for

enzymes to function.

Summary• Enzymes are proteins (made of amino acids)

and can be affected by temperature and pH.– They are folded polypeptide chains!– Where are the made??? ________________

• Enzymes are catalysts, substances that change the rate of a chemical reaction.

• Enzymes are unchanged by the reaction (which is why they can be reused over and over again)!

• Enzymes are named after their substrates.– The name for an enzyme generally ends in “ase”.