Acetyl CoA carboxylase is stimulated by all except-

Ans. is 'd' i.e., Acyl Co A* Acetyl coA carboxylase (ACC) is the rate limiting step of fatty acid synthesis.* ACC converts acetyl coA (the building block of fatty acid) to malonylcoA in the presence of ATP (source of energy), Biotin (coenzyme) and bicarbonate (source of CO2)* Acetyl CoA carboxylase is in a monomeric phosphorylated form when it is inactive. In the presence of signals of high energy, monomeric phosphorylated form gets converted into multimeric/ dephosphorylated form and it becomes active.* REGULATION OF ACC:# As ACC is the rate limiting enzyme of an anabolic pathway (Synthesis), it is stimulated by the anabolic hormone insulin. Insulin mediates its enzyme regulation of most of the metabolic pathways through Protein Phosphatase 2A (PP2A). PP2A dephosphorylates and stimulates Acetyl coA carboxylase.# Glucagon being a catabolic hormone, phosphorylates and inactivates ACC (Glucagon acts through protein kinase A and phosphorylates all enzymes)# Apart from being regulated by hormones through covalent modification, ACC is also allosterically regulated by citrate (tricarboxylic acid), Glutamate (diacarboxylicaminoacid), otherdicarboxylic acids & ATP. All these allosteric regulators stimulate the conversion of monomeric inactive ACC to a multimeric active form. Acyl CoA on the other hand, inhibits ACC by converting multimeric active form to monomeric inactive form.