1. Biochemical Reaction Mechanisms 1. Mechanism of action of  -chymotrypsin 2. Glycolysis: metabolism of glucose 3. Biosynthesis of steroids from squalene

2. Mechanism of action of  -chymotrypsin (An enzyme that hydrolyzes peptides in the digestive system)

3. Catalytic triad: Asp 102, His 57, Ser 195

4.  -chymotrypsin mechanism…

6. Glycolysis Metabolism of glucose to form pyruvate and ATP

7. Glycolysis converts glucose into two pyruvate molecules ä …with the production of 2 ATPs (high energy storage in cells) 1. Isomerization of glucose to fructose 2. Formation of iminium ion; retro aldol to form two 3-carbon sugars (as phosphates) 3. Isomerization of dihydroxyacetone to glyceraldehyde (as phosphates) 4. Oxidation, isomerization, dehydration and dephosphorylation to form pyruvate and ATP

8. Isomerization of glucose to fructose

9. Iminium ion; retro aldol addition

10. Isomerization to glyceraldehyde

11. Oxidation, isomerization and dephosphorylation (ATP forming)

12. Biosynthesis of Steroids from Squalene

13. Squalene (a shark oil terpene)

14. Epoxidation of Squalene

15. Acid-Catalyzed Epoxide Ring Opening; A Ring Formation A

16. Reaction of Alkene with Carbocation; B Ring A BA

17. Cyclization to form C Ring B C A A B

18. Cyclization to form D Ring D C AB

19. Hydride and Methyl Shifts

20. Eventually...Cholesterol !

21. Grading / Final Exam You may replace any of the 5 tests by an improved grade on that section of the Exam. Only the higher grade counts. You need not retake a section if you are happy with your grade on that test. Everyone must take Section 6 (Ch 25, 26, 27 & 29) plus Section 7 (comprehensive; mostly synthesis) Example: Your (best) score on these seven sections plus the sum of your gla scores determines your grade.