Pharmacology General 3a6ff2d2 Trimethoprim acts by: A Inhibiting peptidyl transferase enzyme B Inhibiting dihydrofolate reductase enzyme C Inhibiting Dihydropteroate synthase enzyme D Binds to 50s ribosomal unit and prevents protein synthesis High-Yield Explanation Trimethoprim, Methotrexate and pyrimethamine inhibits dihydrofolate reductase enzyme and prevents formation of Tetrahydrofolic acid and from Dihydrofolic acid.