Oxaloacetate concentration is the most important regulator o…

Oxaloacetate concentration is the most important regulator of the citric acid cycle. Acetyl CoA allosterically induces the activity of a key enzyme to promote an anapleurotic reaction and thus, maintain the balance between oxaloacetate and acetyl CoA concentrations. In the overall process of losing fat, fat cannot be oxidized in the absence of the substrate for this enzyme. Which of the following is the substrate for this key enzyme?