This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Proteins and Amino Acids, Subject name: Biochemistry
[{'content': 'Nitric oxide is synthesized from this amino acid: \nSelect and explain. \nA. Arginine, B. Lysine, C. Leucine, D. Isoleucine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A. Arginine* Nitric oxide is synthesized from L-Arginine* Reaction is catalyzed from enzyme nitric oxide synthase.* Function:# Similar in reactive oxygen species in their function# Potent microbial killer# Produced by endothelial cells and by activated macrophages', 'role': 'assistant'}]