sulfathiazole brands

Molecular formula: C9H9N3O2S2

Sulfonamides are usually bacteriostatic in action. Sulfonamides interfere with the utilization of p-aminobenzoic acid (PABA) in the biosynthesis of tetrahydrofolic acid (the reduced form of folic acid) cofactors in susceptible bacteria. Sulfonamides are structural analogs of PABA and appear to interfere with PABA utilization by competitively inhibiting the enzyme dihydropteroate synthase, which catalyzes the formation of dihydropteroic acid (a precursor of tetrahydrofolic acid) from PABA and pteridine; however, other mechanism(s) affecting the biosynthetic pathway also may be involved. Compounds such as pyrimethamine and trimethoprim, which block later stages in the synthesis of folic acid, act synergistically with sulfonamides. Only microorganisms that synthesize their own folic acid are inhibited by sulfonamides; animal cells and bacteria which are capable of utilizing folic acid precursors or preformed folic acid are not affected by these drugs. The antibacterial activity of the sulfonamides is reportedly decreased in the presence of blood or purulent body exudates. /Sulfonamides/ The sulfonamides are structural analogs of para-aminobenzoic acid (PABA) and competitively inhibit an enzymatic step (dihydropterate synthetase) during which PABA is incorporated into the synthesis of dihydrofolic acid (folic acid). Because dihydrofolate synthesis is reduced, the levels of tetrahydrofolate (folinic acid) formed from dihydrofolate diminish. Tetrahydrofolate is an essential component of the coenzymes responsible for single carbon metabolism in cells. Acting as antimetabolites to PABA, sulfonamides eventually block, in a complex fashion, several enzymes. These enzymes include those needed for the biogenesis of purine bases; for the transfer of desoxyuridine to thymidine; and for the biosynthesis of methionine, glycine, and formylmethionyl-transfer-RNA. This results in suppression of protein synthesis, impairment of metabolic processes, and inhibition of growth and multiplication of those organisms that cannot use preformed folate. The effect is bacteriostatic, although a bactericidal action is evident at the high concentrations that may be found in urine.

Source: PubChem (NCBI) · compound 5340