1. Enzymes

2. Enzymes (catalysts) -
are proteins made of amino acids

3. What do they do?
Help speed up a chemical reaction by lowering the energy needed to start the reaction- also known as the activation energy
Activation energy – “start energy”

4. Enzymes are reusable:
Enzymes are not changed during the reaction, they do the changing

5. an enzyme only acts on it’s perfect match, 1 specific substrate
Enzymes are specific:
an enzyme only acts on it’s perfect match, 1 specific substrate
Puzzle pieces or lock and key ( key only opens one door/lock)

6. Substrate vs. Active Site
Substrate: is what the enzyme acts on
Active site: where substrate binds/ attaches to enzyme

7. How Do Enzymes Work? Action occurs at the enzymes active site
Specific substrate attaches and then is either digested/ synthesized
Enzyme substrate complex = when substrate and enzyme are together.
E+ S  ES  E + P

8. There are two models of enzyme action:
lock & key model  substrate & the enzyme fit together perfectly

9. There are two models of enzyme action:
induced-fit model  enzymes change shape slightly to accommodate the substrate

10. Competitive Inhibitors

11. Factors affecting enzyme action
Some factors can cause an enzyme to be denatured- enzyme shape changes and no longer works

12. Factors affecting enzyme action
Temperature – enzymes work best at certain temperatures
EX: 37oC is best for human enzymes in the body

13. Factors affecting enzyme action
pH – enzymes work best at certain pH;
ex.) Amylase in saliva at pH 7, Pepsin in the stomach at pH 2-3

14. Factors affecting enzyme action
Substrate & enzyme concentrations –depends on how much of the substrate & enzyme is available.

15. Factors affecting enzyme action
Coenzymes – helpers such as vitamins & minerals