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 Intermembrane space Matrix

11. Pyruvate dehydrogenase as seen by electronmicroscopy E. coli enzyme: Mass > 4.5x10 6 24 copies of trans acetylase (E2) 24 copies of pyruvate dehydrogenase (E1) 12 copies of dihydro- lipoyl dehydrogenase Pyruvate + CoASH + NAD +  acetyl-CoA + CO 2 + NADH

12. E1E1 E3E3 E2E2

13. LNC 16.3 Coenzyme A

15. LNC 16.14 Lipoamide

16. LNC Fig. 13-18 FAD/FMN FADH 2 /FMNH 2

17. Fig. 16.6

18. Figure from previous edition of LNC

19. TCA CYCLE Krebs cycle Citric acid cycle

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

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

22. LNC 16.9 Iron-sulfur center in aconitase

23. X

24. Stereospecificity of the aconitase reaction with citrate

25. LNC 16.14

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

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

28. LNC Fig.16.15 the Krebs cycle is amphibolic

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

30. LNC Fig.16-20 Note that the figure 16-16 in the 3 rd edition has an error (there is an O instead of an H) C6C6 C6C6 C4C4 C4C4 C4C4 C2C2 C2C2 C2C2 from oxidation of fatty acids

32. LNC Fig.16.22

33. End of lecture 6 August 12, 2005