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How is Kreb's cycle regulated by ADP?

  1. Feb 13, 2010 #1
    My textbook says,
    I checked the whole citric acid cycle, and only the conversion of succinyl coA requires ADP or GDP. I don't understand how a lack of this would make NADH accumulate. Could anyone explain this. Thanks a lot :smile:
    Last edited: Feb 13, 2010
  2. jcsd
  3. Feb 14, 2010 #2
    All dehydrogenases involved in Krebs are sensitive to the redox potential (mainly NADH / NAD+ ratio). NADH is an inhibitor of those enzymes. Since Electron transport chain & oxidative phosphorylation produce ATP relaying on NADH to provide the energy for ADP phosphorylation to ATP, you can then say ATP is an inhibitor. So the cycle is "turned on" by high ADP/ATP or NAD+ / NADH ratios.

    IIRC, the rate limiting enzime in Krebs is isocitric dehydrogenase.
    Last edited: Feb 14, 2010
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