Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33METABOLIC BIOCHEMISTRYSummer 2005Lecture 6August 12, 2005LNC Chapter 16The Citric Acid CycleKrebs CycleTCA CycleFrom G. Perkins, C. Renken, M.E. Martone,S.J. Young, M. Ellisman, and T. FreyOuter membraneInner membraneIntermembrane spaceMatrixPyruvate dehydrogenase as seen by electronmicroscopyE. coli enzyme:Mass > 4.5x10624 copies of transacetylase (E2)24 copies of pyruvate dehydrogenase (E1)12 copies of dihydro-lipoyl dehydrogenasePyruvate + CoASH + NAD+ acetyl-CoA + CO2 + NADHE1E3E2LNC 16.3Coenzyme ALNC 16.14LipoamideLNC Fig. 13-18FAD/FMNFADH2/FMNH2Fig. 16.6Figure from previous edition of LNCTCA CYCLEKrebs cycleCitric acid cycleLNC 16.11Products from one turn of the Krebs cycleC4C4C4C4C6C2C5C4C6LNC 16.8Citrate Synthaseopen form without substratesclosed from with substrates boundoxaloacetate: yellowacetyl-coA: redLNC 16.9Iron-sulfur center in aconitaseXStereospecificity of the aconitase reactionwith citrateLNC 16.14LNC Fig.16.7the only membrane-bound enzyme in the TCA cycleLNC Fig.16.18regulatory molecules:NADHATP, ADPCa+2key allosteric enzymes:the dehydrogenasescitrate synthaseLNC Fig.16.15the Krebs cycle is amphibolicTHE GLYOXYLATE CYCLELNC Chapter 16, pages 623-626LNC Fig.16-20Note that the figure 16-16 in the 3rd edition has an error(there is an O instead of an H)C6C6C4C4C4C2C2C2from oxidation of fatty acidsLNC Fig.16.22End of lecture 6August 12,
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