This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urea cycle, Subject name: Biochemistry
[{'content': 'Which of the following is the allosteric activator of carbamoyl phosphate synthase I? \nSelect and explain. \nA. Glutamine, B. Oxaloacetate, C. N-acetyl aspaate, D. N-acetyl glutamate', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Carbamoyl phosphate synthase I is the rate-limiting enzyme of the urea cycle Active only in the presence of N-acetylglutamate(NAG), an allosteric activator that enhances the affinity of the synthase for ATP. Arginine is the allosteric activator of NAG synthase.', 'role': 'assistant'}]