When fatty acid biosynthesis is stimulated, beta-oxidation of fatty acids is inhibited. This inhibition occurs mainly because

Question

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Malonyl-CoA is an inhibitor of carnitine acyltransferase I, which is a necessary enzyme for the transport of fatty acids into the mitochondria for beta-oxidation. When fatty acid biosynthesis is stimulated, there is an increase in malonyl-CoA production, which in turn inhibits beta-oxidation. A is incorrect because even though the pool of acetyl-CoA may be depleted, this would actually stimulate beta-oxidation rather than inhibit it. C is incorrect because phosphofructokinase is not directly involved in fatty acid metabolism. D is incorrect because high levels of citrate actually inhibit fatty acid biosynthesis by inhibiting acetyl-CoA carboxylase.

When Fatty Acid Biosynthesis Is Stimulated, Beta-Oxidation of Fatty Acids