1. Enzymes AP Biology

2. General Information Globular proteins Unique 3 dimensional shape Active site: pocket or groove where substrate binds

3. General Information Catalysts Speed up chemical reactions Lower activation energy Not used up in chemical reaction

4. General Information Substrate specific Enzyme substrate pairs Catalase – hydrogen peroxide Sucrase – sucrose

5. Action – Induced Fit Model Substrate binds to enzyme at active site Interaction between substrate and active site

6. Action – Induced Fit Model Bonds in substrate stressed Bonds break Products released

7. Action – Induced Fit Model Substrate binds to enzyme at active site Interaction between substrate and active site Bonds form between reactants

8. Temperature & Rate Increasing temperature increases rate Increase temperature increases speed of molecules Increase speed of molecules increases number of collisions

9. Temperature & Rate Optimal temperature Temperature that produces max. rate.

10. Temperature & Rate Temperature above optimal Enzyme denatured (changes shape) Reaction drops then stops

11. pH & Rate Optimal pH pH with at max. rate

12. pH & Rate Above optimal – rate decreases Lower [H+] interferes with enzyme shape

13. pH & Rate Below optimal – rate decreases Higher [H+] interferes with enzyme shape

14. pH & Rate Extreme changes – rate zero Enzyme denatures

15. Control of Chemical Reactions Inhibitors – Competitive Inhibitor competes with substrate for active site

16. Control of Chemical Reactions Inhibitors – Noncompetitive Inhibitor binds to site other than active site

17. Control of Chemical Reactions Allosteric Enzymes Two conformations – active & inactive Activator stabilizes active form Inhibitor stabilizes inactive form