1. Part II . Protein Dynamics

2. Chapter 14 Enzyme Kinetics

3. 14.1 Enzymes are Biological Catalyst 1878 ------------ enzyme 1913 ------------ Michailis-Menten equation 1926 ------------ urease 1982 ------------ ribozyme 1986 ------------ abzyme

4. Nearly all enzymes are proteins, although a few catalytically active RNA molecules have been identified. Enzyme are catalysts that increase the rate of a chemical reaction without being changed themselves in the process.

5. enormous catalytic power 8 20 10 ----10 • specificity substrate • regulation

6. Holoenzyme = apoenzyme + cofactor Coenzyme Prosthetic group • Monomeric enzyme • Oligomeric enzyme • Multienzyme system

7. 14.2 Enzyme Classification and Nomenclature Oxidoreductases Transferases Hydrolases Lyases Isomerases Ligases

8. ATP:D-glucose-6-phosphotransferase hexokinase enzyme commision E.C.2.7.1.2 class Individual entry subclass sub-subclass

9. 14.3 Kinetics of Enzymes-Catalyzed Reactions

10. Substrate saturation curve for an enzyme-catalyzed reaction

11. 14.3.1 The Michaelis-Menten Equation Enzyme-substrate complex k1 k3 k2 E + S ES E + P

13. Michaelis-Menten Equation Vmax[S] v = ------------- Km + [S] • Constant Km V = Vmax / 2 , Km = [S]

14. Lineweaver-Burk double-reciprocal plot

15. 14.3.2 Effect of PH on Enzymatic Activity

16. 14.3.3 Effect of Temperature on Enzymatic Activity Optimum temperature

17. 14.4 Enzyme Inhibition Any molecule which acts directly on an enzyme to lower its catalytic rate is called an inhibitor.

18. 14.4.1 Irreversible Inhibition Covalent bond

19. 14.4.2 Reversible Inhibition • competitive inhibition

21. noncompetitive inhibition

22. 14.5 Enzyme Activity • Reactive velocity • Active unit (U) • Specific activity • U/mg protein • Turnover Number (kcat )

23. 14.6 RNA and Antibody Molecules as Enzymes 14.6.1 Catalytic RNA Molecules: Ribozymes

24. 14.6.2 Catalytic Antibodies: Abzymes