Question

Which factors would inhibit pyruvate dehydrogenase (PDH) complex to slow the conversion of pyruvate to acetyl-CoA?

1) High levels of ATP
2) High levels of NADH
3) High levels of acetyl-CoA
4) High levels of pyruvate

Answer 1

High levels of ATP, NADH, and acetyl-CoA inhibit the PDH complex, indicating that energy demand is low, leading to feedback inhibition on the conversion of pyruvate to acetyl-CoA.

Step-by-step explanation:

The factors that would inhibit the pyruvate dehydrogenase (PDH) complex and thereby slow the conversion of pyruvate to acetyl-CoA are high levels of ATP, high levels of NADH, and high levels of acetyl-CoA. The presence of these molecules indicates that the cell's energy needs are being met, which triggers a feedback inhibition on the PDH complex. The regulation of PDH is also influenced by phosphorylation; specific kinases phosphorylate PDH, resulting in its inactivation, and phosphatases can reverse this effect to reactivate the enzyme.