This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Amino Acid Metabolism, Subject name: Biochemistry
[{'content': 'Putrescene - a polyamine is formed by decarboxylation of: \nSelect and explain. \nA. Arginine, B. Ornithine, C. Citrulline, D. Adenine', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans: B (Ornithine)Ref: Harper's Illustrated Biochemistry,28th editionExplanation:Polyamines include putrescine, spermidine, spermine.Ornithine is a major precursor for synthesis of polyamines.Conversion of ornithine to putrescine is catalyzed by Ornithine Decarboxylase. (See figure)", 'role': 'assistant'}]