Chemistry 501 Handout 14 Glycolysis, Gluconeogenesis, and the Pentose Phosphate Pathway Chapter 14

1. Dep. of Chemistry & Biochemistry Prof. Indig Chemistry 501 Handout 14Glycolysis, Gluconeogenesis, and the Pentose Phosphate PathwayChapter 14 Lehninger. Principles of Biochemistry. by Nelson and Cox, 5th Edition; W.H. Freeman and Company

2. Major pathways of glucose utilization

3. The first phase of glycolysis (the preparatory phase)

4. The second phase of glycolysis (the payoff phase) O

5. The two phases of glycolysis

6. Three possible catabolic fates of the pyruvate formed in glycolysis

7. 1. Phosphorylation of glucose

8. 2. Conversion of glucose 6-phosphate to fructose 6-phosphate

9. The phosphohexose isomerase reaction anomeric carbon

10. 3. Phosphorylation of fructose 6-phosphate to fructose 1,6-bisphosphate

11. 4. Cleavage of fructose 1,6-bisphosphate

12. The class I aldolase reaction imine

13. 5. Interconversion of the triose phosphates Fate of the glucose carbons in the formation of glyceraldehyde 3-phosphate

14. 6. Oxidation of glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate

15. The glyceraldehyde 3-phosphate dehydrogenase reaction

16. 7. Phosphoryl transfer from 1,3-bisphosphoglycerate to ADP

17. 8. Conversion of 3-phosphoglycerate to 2-phosphoglycerate

18. The phosphoglycerate mutase reaction

19. 9. Dehydration of 2-phosphoglycerate to phosphoenolpyruvate

20. 10. Transfer of the phosphoryl group from phosphoenolpyruvate to ADP

21. Entry of glycogen, starch, disaccharides, and hexoses into the preparatory stage of glycolysis Feeder pathways for glycolysis

22. Feeder pathways for glycolysis

23. Dietary polysaccharides and disaccharides undergo hydrolysis to monosaccharides

24. Glycogen breakdown by glycogen phosphorylase

25. Other monosaccharides enter the glycolytic pathway at several points

26. Conversion of galactose to glucose 1-phosphate Defects in any of the three enzymes in this phatway Cause galactosemia in humans Galactose methabolite involved in galactokinase-deficiency galactosemia

27. Fates of pyruvate under anaerobic conditions: Fermentation Pyruvate is the terminal electron acceptor in lactic acid fermentation no net change in NAD+ or NADH acidification in muscle and blood limits the period of vigorous activity

28. Ethanol is the reduced product in ethanol fermentation tightly bound coenzyme, thiamine pyrophosphate Industrial-scale fermentations yield a variety of common foods and industrial chemicals

29. The alcohol dehydrogenase reaction

30. Thiamine pyrophosphate (TPP) and its role in pyruvate decarboxylation

31. Thiamine pyrophosphate

32. Gluconeogenesis Carbohydrate synthesis from simple precursors

33. Opposing pathways of glycolysis and gluconeogenesis in rat liver

35. Synthesis of phosphoenolpyruvate from pyruvate

36. Role of biotin in the pyruvate carboxylase reaction

37. Alternative paths from pyruvate to phosphoenolpyruvate

38. Citric acid intermediates and many amino acids are glucogenic Citrate Isocitrate a-ketoglutarate Succinyl-CoA Succinate Fumarate Malate Pyruvate oxaloacetate C.A.C. Amino acid catabolism C.A.C. Intermediates

43. Feeder pathways for glycolysis (preparatory phase)

44. General scheme of the pentose phosphate pathway of glucose oxidation

45. Oxidative reactions of the pentose phosphate pathway NADP+

46. Nonoxidative reactions of the pentose phosphate pathway The nonoxidative phase recycles pentose phosphates to glucose 6-phosphate

47. The first reaction catalyzed by transketolase thiamine pyrophosphate General reaction Transfer of a two-carbon group from a ketose donor to an aldose acceptor

48. The reaction catalyzed by transaldolase The second reaction catalyzed by transketolase

49. Role of NADPH in regulating the partitioning of glucose 6-phosphate between glycolysis and the pentose phosphate pathway

50. Role of NADPH and glutathione (GSH) in protecting cells against highly reactive oxygen derivatives