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
[{'content': 'The enzyme involved in the metabolism of clopidogrel and proton pump inhibitors is: \nSelect and explain. \nA. CYP 2A, B. CYP 2B, C. CYP 2C19, D. CYP 2C20', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. C. CYP 2C19a. CYP2C19 has an important function in the metabolism of clopidogrel to its active metabolite, although other members of the CYP family also are involved, (e.g. CYP3A4, CYP3A5, CYP2B6, CYP1A2)b. Omeprazole is a microsomal enzyme inhibitor. It can inhibit the CYP2C19 cytochrome. This cytochrome is responsible for activation of an antiplatelet drug Clopidogrel. Inhibition of CYP2C19 may result in failure of Clopidogrel therapy', 'role': 'assistant'}]