Question

Which of the following statements correctly describe what happens when acetyl-CoA is abundant? (circle all that apply).

Select one or more:

a. Phosphoenolpyruvate carboxykinase is activated

b. If ATP levels are high, oxaloacetate is diverted to gluconeogenesis

c. Phosphofructokinase is activated

d. Pyruvate carboxylase is activated

e. If ATP levels are low, oxaloacetate is diverted to gluconeogenesis.

Answer 1

Phosphoenolpyruvate carboxykinase (PEPCK) is an enzyme in the lyase family used in the metabolic pathway of gluconeogenesis. It converts oxaloacetate into phosphoenolpyruvate and carbon dioxide. It has no relevance with the abundance of acetyl CoA.
acetyl-CoA generated from fatty acid β-oxidation leads to the accumulation of citrate that is a potent inhibitor of phosphofructokinase.

More specifically pyruvate carboxylase is activated by acetyl-CoA. Because acetyl-CoA is an important metabolite in the TCA cycle which produces a lot of energy, when concentrations of acetyl-CoA are high organisms use pyruvate carboxylase to channel pyruvate away from the TCA cycle.

Hence, option, "d" is the correct answer.