Which option is NOT listed as a metabolizing enzyme?

Which option is NOT listed as a metabolizing enzyme?

• A. CYP1A2
• B. P-gp
• C. CYP2B6
• D. CYP3A4

Answer: (C)

Drug-metabolizing enzymes are primarily the cytochrome P450 enzymes that chemically modify drugs, making them easier to eliminate. Among the options, the cytochrome P450 family members—CYP1A2, CYP2B6, and CYP3A4—are classic examples of these metabolizing enzymes. P-glycoprotein, on the other hand, is a drug transporter. It moves drugs across cell membranes and affects absorption and distribution, but it does not metabolize drugs. So the option that is not a metabolizing enzyme is the one involving P-glycoprotein. (For clarity, CYP2B6 is indeed a metabolizing enzyme.)

Drug-metabolizing enzymes are primarily the cytochrome P450 enzymes that chemically modify drugs, making them easier to eliminate. Among the options, the cytochrome P450 family members—CYP1A2, CYP2B6, and CYP3A4—are classic examples of these metabolizing enzymes. P-glycoprotein, on the other hand, is a drug transporter. It moves drugs across cell membranes and affects absorption and distribution, but it does not metabolize drugs. So the option that is not a metabolizing enzyme is the one involving P-glycoprotein. (For clarity, CYP2B6 is indeed a metabolizing enzyme.)