This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pharmacology, Subject name: Pharmacology
All the following enzymes are involved in the metabolism of xenobiotics except 
Select and explain. 
A. Hydroxylase, B. Cytochrome oxidase, C. Cytochrome P450, D. Methylase
B: Cytochrome oxidase
Answer: B: Cytochrome oxidase 
Explanation: Oxidation, reduction, and hydroxylation are phase 1 reactionsCyp. 450 is the most common enzyme involved in the metabolism of various drugs in phase 1 and phase 2.Methylase - phase 2 reactionRef: Goodman Gillman 11th ed, pg 71