sulfaquinoxaline brands

Molecular formula: C14H12N4O2S

Bacteriostatic. Sulfonamides interfere with the biosynthesis of folic acid in bacterial cells; they compete with paraaminobenzoic acid (PABA) for incorporation in the folic acid molecule. By replacing the PABA molecule and preventing the folic acid formation required for DNA synthesis, the sulfonamides prevent multiplication of the bacterial cell. Susceptible organisms must synthesize their own folic acid; mammalian cells use preformed folic acid and, therefore, are not susceptible. Cells that produce excess PABA or environments with PABA, such as necrotic tissues, allow for resistance by competition with the sulfonamide. /Sulfonamides/ Sulfonamides are structural analogs and competitive antagonists of para-aminobenzoic acid (PABA) and thus prevent normal bacterial utilization of PABA for the synthesis of folic acid (pteroylglutamic acid). More specifically, sulfonamides are competitive inhibitors of dihydropteroate synthase,the bacterial enzyme responsible for the incorporation of PABA into dihydropteroic acid, the immediate precursor of folic acid. Sensitive microorganisms are those that must synthesize their own folic acid; bacteria that can utilize preformed folate are not affected. Bacteriostasis induced by sulfonamides is counteracted by PABA competitively. Sulfonamides do not affect mammalian cells by this mechanism, since they require preformed folic acid and cannot synthesize it. /Sulfonamides/

Source: PubChem (NCBI) · compound 5338