Clinical Presentation Curriculum A Guide to Intermediary Metabolism Jack Blazyk, Ph.D. 2003-2004

1. Clinical Presentation CurriculumA Guide toIntermediary MetabolismJack Blazyk, Ph.D.2003-2004

2. 2

3. 3 Thermodynamics In an actively functioning pathway, the DG for ALL reactions is NEGATIVE Enzyme Regulation Covalent Modification (e.g., reversible phosphorylation) Allosteric Regulation OR Genetic Regulation

4. 4 High-Energy Phosphates Enol Acyl Example Phosphoenolpyruvate (PEP) Example 1,3-Bisphosphoglycerate Amino Pyro (Phosphoanhydride) Example Adenosine triphosphate (ATP) Example Creatine phosphate Hydrolysis of Phosphates Enol -15 Acyl -10 Amino -10 Pyro -7 Adenosine Pool Hydrolysis of ATP ATP ADP AMP

5. Nicotinamide Adenine Dinucleotide Nicotinamide Adenine Dinucleotide Phosphate NAD+ + 2e- + H+ NADH Oxidized Reduced NADP+ + 2e- + H+ NADPH Oxidized Reduced Flavin Adenine Dinucleotide FAD + 2e- + 2H+ FADH2 Oxidized Reduced O CoA - S ~ C – CH3 5 Electron Transfer Acyl Group Transfer Coenzyme A ADP + Pantothenic Acid + SH CoA - SH Acetyl-CoA

6. 6 Citric Acid Cycle or Tricarboxylic acid (TCA) Cycle or Krebs Cycle Located in mitochondrial matrix Citrate - COO- Citric Acid Sneak Preview 1. C2 + C4 C6 2. C6 C5 + CO2 + 2e- Oxidative Decarboxylations 3. C5 C4 + CO2 + ~P + 2e- 4. C4C4 + 4e-

7. O | | CH3 - C - S - CoA 3 H2O 3 NAD+ 1 FAD GDP + Pi Citrate Synthase Aconitase 7 Isocitrate Dehydrogenase a-KG Dehydrogenase Oxidative Decarboxylations Succinate Thiokinase Succinate Dehydrogenase Fumarase Malate Dehydrogenase Out In CoA - SH 2 CO2 3 NADH + 3 H+ 1 FADH2 GTP + H2O

8. 8 Tap-Off Points PEP Carboxykinase Malic Enzyme Malate Pyruvate NADP+ NADPH + H+ + CO2 Anaplerotic Pathway Pyruvate Carboxylase Pyruvate Oxaloacetate ATP + CO2 ADP + Pi Biotin (a water-soluble B vitamin) is a coenzyme Allosterically activated by Acetyl-CoA

9. Complex INADH-Q Reductase • Transfers electrons from NADH to Q • NADH + H+ + Q NAD+ + QH2 • Flavin Mononucleotide (FMN) • Iron-sulfur (Fe-S) proteins • Complex IIICytochrome Reductase • Transfers electrons from QH2 to Cyt c • QH2 + 2Cyt c(Fe+3) Q + 2H++ 2Cyt c(Fe+2) • Cytochrome b (2 types) • Iron-sulfur (Fe-S) proteins • Cytochrome c1 • Complex IVCytochrome Oxidase • Transfers electrons from Cyt c to O2 • 2Cyt c(Fe+2) + ½O2 + 2H+ 2Cyt c(Fe+3) + H2O • Cytochrome a • Cytochrome a3 • Copper (Cu) • Complex IISuccinate-Q Reductase • Transfers electrons from Succinate to Q • Succinate + Q Fumarate + QH2 • Flavin Adenine Dinucleotide (FAD) • Iron-sulfur (Fe-S) proteins Oxidative Phosphorylation 9 Electron Transport Chain = Respiratory Chain • 4 Membrane-Bound Complexes • I – NADH-Q Reductase • II – Succinate-Q Reductase • III – Cytochrome Reductase • IV – Cytochrome Oxidase • 2 Mobile Electron Carriers • Ubiquinone (Coenzyme Q) • Cytochrome c

10. 10 Chemiosmotic Mechanism • Proposed by Peter Mitchell • Proton Motive Force • PMF = DpH + DY

11. GTP + ADP GDP + ATP [ATP] + ½ [ADP] [ATP] + [ADP] + [AMP] ATP Production via CAC and Ox Phos 11 3 NADH ~9 ATP 1 FADH2 ~2 ATP 1 GTP 1 ATP ~12 ATP per Acetyl-CoA Regulation of CAC and Ox Phos • Availability of Acetyl-CoA • Availability of O2 • Energy Charge = • Respiratory Control Electron Transport Inhibitors COCN -N3-Rotenone X X

12. X Atractyloside Oligomycin OH X NO2 NO2 O - + H+ NO2 NO2 H+ H+ H+ X 12 Oxidative Phosphorylation Inhibitors Uncouplers 2,4-Dinitrophenol

13. 13

14. 14

15. 15

16. 16

17. 17

18. 18

19. 19

20. 20

21. 21

22. 22

23. 23

24. 24

25. 25

26. 26

27. 27

28. 28

29. 29

30. 30

31. 31

32. 32

33. 33

34. 34

35. 35

36. 36

37. 37

38. 38

39. R-COOH 39

40. 40 Fatty Acid Oxidation

41. 41

42. 42

43. 43 Fatty Acid Biosynthesis

44. 44 Regulation

45. 45

46. 46 Triglyceride Metabolism

47. 47 Lipogenesis Lipolysis

48. 48

49. 49 Amino Acid Metabolism

50. Liver Matrix Cytoplasm 50 Amino Group Shuttles Urea Cycle From Harper’sBiochemistry, Murray et al., 25th ed., 2000, Fig. 31-14