Mycophenolate mofetil suppresses lymphocyte proliferation by inhibiting which enzyme?

• A IMP dehydrogenase ✓
• B Ribonucleotide reductase
• C Dihydrofolate reductase
• D Thymidylate synthase

Explanation

Mycophenolic acid reversibly inhibits IMP dehydrogenase, the rate limiting enzyme of the de novo guanine nucleotide synthesis pathway. Lymphocytes depend almost entirely on this de novo pathway because they lack the salvage pathway, giving the drug relative selectivity for T and B cells. Thymidylate synthase and dihydrofolate reductase are targets of fluorouracil and methotrexate respectively, and ribonucleotide reductase is targeted by hydroxyurea.

Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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