recitaon*3*tca,* glyoxylate& ureacycle* - web publishing · pdf fileu tarate met h ionine...
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Factors controlling the ac'vity of the Pdh product inhibi'on.
Factors controlling the ac'vity of the Pdh. Covalent modifica'on in the eukaryo'c complex.
The TCA cycle showing enzymes, substrates and products. The GTP generated during the succinate thiokinase (succinyl-‐CoA synthetase) reac'on is equivalent to a mole of ATP by virtue of the presence of nucleoside diphosphokinase. The 3 moles of NADH and 1 mole of FADH2 generated during each round of the cycle feed into the oxida've phosphoryla'on pathway. Each mole of NADH leads to 3 moles of ATP and each mole of FADH2 leads to 2 moles of ATP. Therefore, for each mole of pyruvate which enters the TCA cycle, 12 moles of ATP can be generated.
The overall stoichiometry of the TCA cycle is: acetyl-‐CoA + 3NAD+ + FAD+ + GDP + Pi + 2H2O -‐-‐-‐-‐> 2CO2 + 3NADH + FADH2 + GTP + 2H+ + HSCoA
Note the endothermic Mdh, +29.7kJ/mol and the exothermic citratre synthase, -‐31.4 kJ/mol. Why should Mdh have evolve to favor malate and not OAA?