This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of lipid, Subject name: Biochemistry
[{'content': 'Activator of acetyl CoA carboxylase is \nSelect and explain. \nA. Malonyl CoA, B. Acetoacetate, C. Citrate, D. Palmitoyl CoA', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Acetyl CoA Carboxylase It is the key enzyme; citrate activates this enzyme. The citrate level is high only when both acetyl CoA and ATP are abundant. Covalent modification is another regulatory mechanism. Phosphorylation inactivates acetyl CoA carboxylase (similar to glycogen synthase under the effect of glucagon). Hence fatty acid synthesis decreases when glucose level is low. The enzyme is inhibited by palmitoyl CoA, the end product.Ref: DM Vasudevan - Textbook of Biochemistry, 8th edition, page no: 139', 'role': 'assistant'}]