Dapsone is the cornerstone of MDT for leprosy. Its mechanism of action is inhibition of which enzyme in the folate synthesis pathway?
- A Dihydropteroate synthase (DHPS) ✓
- B Dihydrofolate reductase (DHFR)
- C Thymidylate synthase
- D DNA gyrase
Correct answer: A. Dihydropteroate synthase (DHPS)
Explanation
Dapsone is a sulfone that competitively inhibits dihydropteroate synthase (DHPS), the same enzyme targeted by sulfonamides. This blocks folic acid synthesis in M. leprae. Resistance arises from mutations in folP1 (encoding DHFR is inhibited by trimethoprim, not dapsone). Dapsone is bactericidal against M. leprae.
Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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