1. Chapter 23 Gluconeogenesis, Glycogen Metabolism, and the Pentose Phosphate Pathway

2. 23.1 Gluconeogenesis 23.1.1 Overview 23.1.2 Gluconeogenesis Is Not Merely the Reverse of Glycolysis

4. 1. Pyruvate carboxylase

5. 2. Transport of oxaloacetate out of the michondrion Pyruvate carboxylase Malate dehydrogenase Malate dehydrogenase

6. 3. PEP Carboxykinase

7. 4. Fructose-1,6-Bisphosphatase

8. 5. Glucose-6-Phosphatase

9. 23.1.3 Energy Used Pyruvate carboxylase 1ATP * 2 = 2ATP PEP carboxykinase 1GTP * 2 = 2GTP Phosphoglycerate kinase 1ATP * 2 = 2ATP TOTAL = 6ATP

10. 23.1.4 Precursors for gluconeogenesis Glycerol Lactate Pyruvate Citric acid cycle intermidiates The carbon skeletons of the amino acid

11. The cori cycle

12. 23.1.4 Reciprocal Regulation of Glycolysis and Gluconeogenesis

15. 23.2 Glycogen Metabolism 23.2.1 Glycogen Catabolism • Glycogen phosphorylase • Glycogen-debranching enzyme

19. glycogen + Pi glycogen + G-1-P (n residues) (n-1 residues) phosphoglucomutase G-1-P G-6-P

20. 23.2.2 Glycogen Synthesis • UDP-glucose pyrophosphorylase • glycogen synthase • branching enzyme • [amylo-(1-4 1-6) transglycosylase]

25. 23.2.3 Control of Glycogen Metabolism • Allosteric control and covalent modification Phosphorylase kinase ATP ADP Phosphorylase b phosphorylase a (dephosphorylated , (phosphorylated, inactive) active) Pi Protein phosphatase I

26. Protein phosphatase Pi Glycogen synthase b Glycogen synthase a (phosphorylated , (dephosphorylated, inactive) active) ADP ATP Protein kinase A

27. Hormones Regulate Glycogen Synthesis and Degradation Insulin

28. Glucagon Epinephrine

29. Cortisol

30. 23.3 The Pentose Phosphate Pathway 23.3.1 Overview Hexosephosphate shunt Hexose monophosphate shunt Phosphogluconate pathway 23.3.2 Main Reaction of the Pathway

32. 1. The oxidative steps of the pentose phosphate pathway Glucose-6-phosphate dehydrogenase Gluconolactonase 6-Phosphogluconate dehydrogenase

36. 2. The nonoxidative steps of the pentose phosphate pathway Phosphopentose isomerase Phosphopentose epimerase Transketolase Transaldolase

37. Phosphopentose isomerase

40. Transaldolase

42. 23.3.3 Utilization of G-6-P Depends on the Cell’s Needs for ATP, NADPH, and Ribose-5-P