The Pyruvate Dehydrogenase System Flashcards
Anaplerotic
(Filling up) reactions that replenish the TCA cycle intermediates
Major anaplerotic reaction
Pyruvate Carboxylase is a major anaplerotic reaction in mammalian tissues
Pyruvate+CO2+ATP+H2O—->Oxaloacetate+ADP+Pi
Pyruvate dehydrogenase
Links glycolysis to the TCA cycle
Pyruvate—>Acetyl-CoA
Gives off H2 and CO2
Entry of pyruvate into the mitochondria
Pyruvate translocase transports pyruvate into the mitochondria in symport with H+
Reactions of the PDH complex
Multi enzyme with 3 type subunits Pyruvate dehydrogenase (E1) Dihydrolipoyl transacetlyase (E2) Dihydrolipoyl dehydrogenase (E3) E2&E3 are inhibited by NADH, acetyl CoA and CO2 Activated by pyruvate, NAD+ and HSCoA
Activation and inhibition of the PDH
Pyruvate dehydrogenase kinase phosphorylates the PDH inactivating it (uses ATP)
Pyruvate dehydrogenase phosphatase cleaves the phosphate from the inactive form activating it. Uses water and produces Pi