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': 'Allosteric activator of NAG synthase is: \nSelect and explain. \nA. Aspaate, B. Arginine, C. CPS-I, D. CPS-II', 'role': 'user'}, {'content': 'Answer: B \nExplanation: NAG is an allosteric activator of CPS-I (rate limiting enzyme) NAG is synthesized from N-acetyl glutamate synthase or NAG synthase, for which arginine is the activator.', 'role': 'assistant'}]