Answer:
The correct answer is pyruvate dehydrogenase; NADH.
Explanation:
Entry to the citric acid cycle involves the generation of acetyl CoA. The enzyme that catalyzes the production of acetyl CoA is pyruvate dehydrogenase. This enzyme is negatively regulated by NADH in a high-energy charge situation.
Acetyl CoA is obtained by the decarboxylation of pyruvate which is catalyzed by the pyruvate dehydrogenase complex. Later, the excess of NADH represents a feedback inhibition in the enzyme.
