This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
[{'content': 'Man can not synthesise ascorbic acid due to deficiency of enzyme \nSelect and explain. \nA. L gulanolactone oxidase, B. Gluco cerbrosidase, C. Peroxidase, D. Lysyl oxidase', 'role': 'user'}, {'content': 'Answer: A \nExplanation: ASCORBIC ACID (VITAMIN C):\n\nThe active form of vitamin C is ascorbic acid.\xa0\nIts main function is as a reducing agent.\xa0\nVitamin C is a coenzyme in hydroxylation reactions (for example, hydroxylation of prolyl and lysyl residues in collagen) where its role is to keep the iron (Fe) of hydroxylases in the reduced, ferrous (Fe+2) form.\xa0\nThus, vitamin C is required for the maintenance of normal connective tissue as well as for wound healing. Vitamin C also facilitates the absorption of dietary nonheme iron from the intestine by reduction of the ferric form (Fe+3) to Fe+2.\nMan and other primates, guinea pigs and bats cannot synthesize ascorbic acid due to the deficiency of a single enzyme namely L-gulonolactone oxidase.\n\nKey Concept:\nMan cannot synthesize ascorbic acid due to the deficiency of a single enzyme namely L-gulonolactone oxidase.\nRef : Lippincott’s illustrated reviews for biochemistry , 7th edition.', 'role': 'assistant'}]