1. Figure 6.1 The complexity of metabolism

2. Figure 6.5 The relationship of free energy to stability, work capacity, and spontaneous change

3. Figure 6.6 Energy changes in exergonic and endergonic reactions

4. Figure 6.7 Disequilibrium and work in closed and open systems

5. Figure 6.8 The structure and hydrolysis of ATP

6. Figure 6.9 Energy coupling by phosphate transfer

7. Figure 6.10 The ATP cycle

8. Figure 6.11 Example of an enzyme-catalyzed reaction: Hydrolysis of sucrose

9. Figure 6.12 Energy profile of an exergonic reaction http://www.stolaf.edu/people/giannini/flashanimat/enzymes/transition%20state.swf

10. Figure 6.13 Enzymes lower the barrier of activation energy

11. Figure 6.14 The induced fit between an enzyme and its substrate

12. Figure 6.15 The catalytic cycle of an enzyme

13. Figure 6.16 Environmental factors affecting enzyme activity

14. Characterizing enzymes V max - rate when enzyme is saturated with substrate K M – substrate concentration that allows reaction to proceed at 1/2 V max K M – useful as a measure of how tightly an enzyme binds its substrate –Low K M means tight binding, high K M means weak binding Enzyme kinetics

15. Characterizing enzymes Turnover number: V max /enzyme concen. – typically about 1000 substrate molecules processed per second per enzyme molecule, but can be much higher

16. EnzymeTurnover number (per second) Carbonic anhydrase600,000 Acetycholinesterase25,000 Amylase18,000 Penicillinase2,000 DNA Polymerase15

17. Measuring enzyme activity One unit of an enzyme is defined as the amount that will catalyze a defined amount of substrate in one minute under specified conditions. For catalase: one unit decomposes 1  mole H 2 O 2 at 25 0 C at pH 7.

18. What to measure for rate? Amount of substrate used over a specified time. OR Amount of product accumulated over a specified time. Which to use???

19. Figure 6.17 Inhibition of enzyme activity

20. Figure 6.18 Allosteric regulation of enzyme activity

21. Figure 6.19 Feedback inhibition

22. Figure 6.20 Cooperativity