1. Enzymes

2. What Are Enzymes? Most enzymes are Proteins with specific shapes
Act as Catalyst to accelerates a reaction
Not permanently changed in the process

3. Enzymes Are specific for what they will catalyze Are reusable
End in –ase
-Protease
-Lactase
-Catalase

4. How do Enzymes Work?
Enzymes work by lowering activation energy

5. Enzymes Without Enzyme With Enzyme Free Energy
Progress of the reaction
Reactants
Products
Free energy of activation

7. Enzyme-Substrate Complex
The substance (reactant) an enzyme acts on is the substrate
Enzyme
Joins
Substrate

8. Active Site
A restricted region of an enzyme molecule which binds to the substrate.
Enzyme
Substrate
Active Site

9. Affecting Enzyme Activity
Three factors:
1. Environmental Conditions
2. Cofactors and Coenzymes
3. Enzyme Inhibitors

10. 1. Environmental Conditions
1. Temperature
- High temps may denature (unfold) the enzyme.
- Low temps do not affect enzyme
2. pH (most like pH near neutral)
- Outside optimal range enzyme denatures
3. Concentration
- Activity increases as concentration increases until it reaches a saturation point

11. 2. Cofactors and Coenzymes
Inorganic substances (minerals like zinc and iron) and organic substances (vitamins) are sometimes need for proper enzymatic activity.
Example:
Iron must be present in the quaternary structure - hemoglobin in order for it to pick up oxygen.

12. Enzyme Inhibitors
a. Competitive inhibitors: resemble an enzyme’s normal substrate and compete with it for the active site
Enzyme
Substrate
Competitive inhibitor

13. Enzyme Inhibitors
b. Noncompetitive inhibitors: do not bind at active site, but bind to another part of the enzyme causing a change in shape
Enzyme
Noncompetitive
Inhibitor
Substrate
active site
altered