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: Pharmacology
[{'content': 'All of the following enzymes and their reactions are involved in the metabolism of Xenobiotics, EXCEPT: \nSelect and explain. \nA. Cytochrome oxidase, B. Cytochrome p 450, C. Methylation, D. Hydroxylation', 'role': 'user'}, {'content': "Answer: A \nExplanation: Cytochrome oxidase is not mentioned as an enzyme in the metabolism of xenobiotics but Cytochrome P450 and Hydroxylation reactions are involved in Phase-1 metabolic reactions and Methylation forms a pa of phase II reactions. Ref: Harpers Biochemistry, 27th Edition, Page 633; Lippincott's Illustrated Reviews: Pharmacology, 4th Edition, Page 14; Goodman and Gilman's The Pharmacological Basis of Therapeutics, 11th Edition, Page 44", 'role': 'assistant'}]