Question

The pyruvate dehydrogenase complex is subject to allosteric control, especially inhibition by reaction products. The main regulatory process controlling pyruvate dehydrogenase's activity in eukaryotes is:
a. Exchange of ADP and ATP on the pyruvate dehydrogenase complex.
b. AMP binding to and activating the enzyme.
c. Phosphorylation by ATP, which turns the complex on, and dephosphorylation, which turns the complex off.
d. Phosphorylation by ATP, which turns the complex off, and dephosphorylation, which turns the complex on.

Answer 1

Answer:

d. Phosphorylation by ATP, which turns the complex off, and dephosphorylation, which turns the complex on

Explanation:

Pyruvate dehydrogenase complex (PDC) is a complex enzymes which is responsible for the conversion of pyruvate into acetyl-CoA, NADH and CO2  through oxidative decarboxylation.

Pyruvate dehydrogenase is one of the main component of PDC that catalyze conversion of pyruvate to acetyl-CoA. Pyruvate dehydrogenase (PDH) enzymes is first modified by covalent modification in the pyruvate dehydrogenase complex. Pyruvate dehydrogenase kinase undergo phosphorylation with ATP and inactivates PDH which turns the complex off. then the pyruvate dehydrogenase phosphatase support dephophorylation which turns the complex ON.

Hence, the correct option is d.