1. ENZYMES made of Proteins

2. 100s to 1000s of chemical rxn in human body
Enzymes speed up rxn by millions and even billions of times
Single enzyme molecule acts on about 1000 substrate molecules/second.

3. IMPORTANCE OF ENZYMES Enzymes are biological catalysts.
Lower the amount of energy needed for rxn
Not changed by rxn
Not used up by rxn

4. They lower the amount of energy needed for a reaction.
Reaction pathway
without enzyme
Activation energy
Activation
energy
with enzyme
Reactants
Products

5. Responsible for metabolism:
Catabolism: breaking apart molecules (hydrolysis)
Anabolism: building molecules (dehydration synthesis)

6. Dehydration synthesis
Hydrolysis

7. Lipase-lipids Protease-proteins Sucrase-sucrose
Most enzymes are named after the substrate they work on (usually ending in “-ase”).
Lipase-lipids
Protease-proteins
Sucrase-sucrose

9. ENZYME STRUCTURE

10. Substrate Reactants that enzymes work on.
Can be a big molec that needs broken down or small molec that need to be joined together.

11. Product
The altered substrate produced at the end of the reaction.

12. Active Site
The place on the enzyme where the substrate and enzyme interact.
The substrate fits like a key in the “lock” of the active site.

13. Enzyme Specificity
Enzymes are very specific about which types of substrates they can work on.
B/C of this, a different enzyme is needed for almost every rxn in the body.

17. Enzyme Animation

18. Denaturation
An enzyme’s active site changes shape, which can stop or slow down biological activity, usually permanent
Causes:
Temperature change
pH change

19. pH
There is a range of tolerance specific to each enzyme

20. Temperature
There is a range of tolerance specific to each enzyme

22. Inhibitors Substances that interfere with the action of the enzyme.
2 types
Competitive
Noncompetitive
Ex. Toxins, poisons, antibiotics

23. Competitive Inhibitors
Are able to bind at the active site and block the way for the substrate.

24. Noncompetitive Inhibitors
Bind someplace other than the active site causing a change in the active site.
Substrate can no longer bind.

25. Coenzymes Another chemical (non- protein) that helps enzymes do work.
Example vitamins