The relationship between sulphonamide and PABA is: (A) Metabolic antagonism, (B) Synergism, (C) Intermediate compound formation, (D) Chelation
Answer is A. Sulfonamides have structural similarity with PABA .therefore, they competitively inhibit the enzyme responsible for the incorporation of PABA into dihydropteroic acid, the immediate precursor of folic acidRef: DM Vasudevan, 7th edition, page no: 491, 61