Sulfadoxin-d4 is intended for use as an internal standard for the quantification of sulfadoxin by GC- or LC-MS. Sulfadoxin is a sulfonamide antibiotic that inhibits dihydropteroate synthetase (DHPS), an enzyme involved in folic acid synthesis.1 Sulfadoxin competes with 4-aminobenzoate (PABA), the native substrate of DHPS, and inhibits PABA incorporation into folic acid.2 Folate is essential for purine and pyrimidine synthesis, therefore, sulfadoxin has antiproliferative activity in non-resistant P. falciparum.2,3 Sulfadoxin inhibits growth of P. falciparum in vitro, but potency varies between non-resistant (IC50 = 4 ng/ml) and resistant strains (IC50 = 3,970 ng/ml).3
1.Brooks, D.R., Wang, P., Read, M., et al.Sequence variation of the hydroxymethyldihydropterin pyrophosphokinase: dihydropteroate synthase gene in lines of the human malaria parasite, Plasmodium falciparum, with differing resistance to sulfadoxineEur. J. Biochem.224(2)397-405(1994) 2.Hyde, J.E.Exploring the folate pathway in Plasmodium falciparumActa. Trop.94(3)191-206(2005) 3.Wang, P., Read, M., Sims, P.F.G., et al.Sulfadoxine resistance in the human malaria parasite Plasmodium falciparum is determined by mutations in dihydropteroate synthetase and an additional factor associated with folate utilization.Mol. Microbiol.23(5)979-986(1997)