Final answer:
Excess levels of NADH inhibit the enzyme pyruvate dehydrogenase, hence preventing the conversion of pyruvate to acetyl-CoA; the answer is option C, Pyruvate Dehydrogenase.
Step-by-step explanation:
Excess levels of NADH prevent the enzyme, pyruvate dehydrogenase from catalyzing the conversion of pyruvate to acetyl-CoA. The correct answer is C. Pyruvate Dehydrogenase.
Pyruvate dehydrogenase plays a crucial role in the metabolic pathway, linking glycolysis to the citric acid cycle by converting pyruvate into acetyl-CoA. However, when NADH levels are high, indicating that the energy needs of the cell are low, pyruvate dehydrogenase activity is inhibited to prevent the unnecessary conversion of pyruvate. This inhibition ensures the cell maintains an efficient and balanced use of its energy resources.