METABOLIC BIOCHEMISTRY Summer 2005 Lecture 6 August 12, 2005

1. METABOLIC BIOCHEMISTRY Summer 2005 Lecture 6 August 12, 2005

2. LNC Chapter 16 The Citric Acid Cycle Krebs Cycle TCA Cycle

6. From G. Perkins, C. Renken, M.E. Martone, S.J. Young, M. Ellisman, and T. Frey

10. Outer membrane Inner membrane Matrix Intermembrane space

11. Pyruvate dehydrogenase as seen by electronmicroscopy E. coli enzyme: Mass > 4.5x106 24 copies of trans acetylase (E2) 24 copies of pyruvate dehydrogenase (E1) 12 copies of dihydro- lipoyl dehydrogenase Pyruvate + CoASH + NAD+ acetyl-CoA + CO2 + NADH

12. E1 E3 E2

13. Coenzyme A LNC 16.3

15. Lipoamide LNC 16.14

16. FAD/FMN FADH2/FMNH2 LNC Fig. 13-18

17. Fig. 16.6

18. Figure from previous edition of LNC

19. TCA CYCLE Krebs cycle Citric acid cycle

20. Products from one turn of the Krebs cycle C2 C6 C4 C6 C4 C5 C4 C4 C4 LNC 16.11

21. Citrate Synthase oxaloacetate: yellow acetyl-coA: red open form without substrates closed from with substrates bound LNC 16.8

22. Iron-sulfur center in aconitase LNC 16.9

23. X

24. Stereospecificity of the aconitase reaction with citrate

25. LNC 16.14

26. the only membrane- bound enzyme in the TCA cycle LNC Fig.16.7

27. regulatory molecules: NADH ATP, ADP Ca+2 key allosteric enzymes: the dehydrogenases citrate synthase LNC Fig.16.18

28. the Krebs cycle is amphibolic LNC Fig.16.15

29. THE GLYOXYLATE CYCLE LNC Chapter 16, pages 623-626

30. from oxidation of fatty acids C2 C4 C6 C4 C6 C4 C2 C2 LNC Fig.16-20 Note that the figure 16-16 in the 3rd edition has an error (there is an O instead of an H)

32. LNC Fig.16.22

33. End of lecture 6 August 12, 2005