Why does increase in NADH only inhibits pyruvate decarboxylase but not phosphofructokinase? Is there a reason for that or it is just like that

Question

anonymous · Answer

I think it could be because PFK is not an enzyme affected by this coenzime: NAD/NADH since this is a transporter of H+ with a great cappacity to donate electrons, interferes in the two redox reactions that take place during glicolysis. 
PFK is a kinase and as such its mission is to transport phosphate groups.

anonymous · Answer

This is a bit tricky so I want to ask a question first: do you mean pyruvate decarboxylase or pyruvate dehydrogenase, which is the first part of the decarboxylation of pyruvate? I ask because pyruvate dehydrogenase is inhibited by NADH. NADH has an effect by inhibiting a phosphatase that activates pyruvate dehydrogenase. This makes sense if you look at it as a system: NADH is one of the end products of the decarboxylation, which provides acetyl coA for cellular respiration. I hope this makes some sense and is useful, best wishes

anonymous · Answer

I do not know, but i can speculate upon this. If Phosphofructokinase i inhibited that would limit the production of Pyruvat, but on the other hand if Pyruvat dehydrogenase would be inhibited then the Pyruvat still in the cycle aswell as in form of Dihydroxyacetone phosphate would have no where to go except to go through the Aerobic glycolys. And that's not so good. If both would be blocked simutaniously, yes it would limit the input but aswell as Anaerobic pathway it could take, so the remaining Precoursers to pyruvat remaining the the cycle after Fructose 1,6-Biphosphate would be unoptimially utilized. And we know how much the body hates to throw away extra energy molecules. Aswell as the complication this can lead to. Incase it's not Pyruvate Dehydrogenase you refered to but Pyruvat Carboxylase which converts Pyruvat to Oxaloacetate in Krebs cycle, then the PDF below should be able to clarify any question you'd have. I think this PDF should help you get a complete understand of PC: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1220216/pdf/10229653.pdf If it is PDC you auctally mean, i lack any knowlegde to the subject and how it's related to the glycolysis.