background: the present study was formulated in order to determine pol­ymorphism of dihydropteroate synthetase gene (dhps) of plasmodium vivax (p . vivax ) in hormozgan province, southern iran and mutations at codons 382, 383, 512, 553, and 585 associated with resistance of p. vivax to sulfadoxine. method : one-hundred eighteen isolates of p. vivax were prepared within 2007-2008 to determine di...

The implication of dihydrofolate reductase and dihydropteroate synthetase gene mutations in modification of Plasmodium falciparum characteristics Abstract Background: The Plasmodium falciparum dihydrofolate reductase (DHFR) and dihydropteroate synthetase (DHPS) are enzymes of central importance in parasite metabolism. The dhfr and dhps gene mutations are known to be associated with sulphadoxine...

Aerobacter aerogenes mutant 62-1 AC requires high concentrations of 4-aminobenzoate for growth. The mutant accumulates N-glucosyl-4-aminobenzoate and has an intact 4-aminobenzoate synthetase (Bacher, Gilch, Rappold, and Lingens, Z. Naturforsch. 28 c, 614-617 [1973]). On the other hand the ability of the mutant to synthesize dihydropteroate is markedly reduced. The dihydropteroate synthetase lev...

An 8.5-megadalton plasmid coding for sulfonamide resistance was found in a clinical isolate of Neisseria meningitidis, as demonstrated by plasmid elimination and transformation experiments. The plasmid complemented a mutation which determines the production of a thermosensitive dihydropteroate synthetase in Escherichia coli, thus suggesting that the mechanism of resistance involved a plasmid-en...

The molecular interaction of various sulfones and sulfonamides with partially purified dihydropteroate synthetase from Neisseria meningitidis M-166 has been examined. The mode of action of the sulfones was similar to that of the sulfonamides. Both groups of drugs were competitive inhibitors of dihydropteroate synthetase with respect to p-aminobenzoate in a partially purified enzyme preparation....

Extracts from Neisseria meningitidis and N. gonorrhoeae with varying susceptibility to sulfanilamide have been investigated for dihydropteroate synthetase activity. Sulfanilamide was a competitive inhibitor of dihydropteroate synthetase with respect to p-aminobenzoate in extracts from both species. Though the K(m) for p-aminobenzoate was unaffected, the K(i) for sulfanilamide increased and the ...

The inhibitory action of various diphenylsulfones and sulfonamides on dihydropteroate synthetase partially purified from Escherichia coli was examined. 4,4'-Diaminodiphenylsulfone (DDS; I(50) = 2 x 10(-5) M) and the monosubstituted derivatives 4-amino-4'-formamidodiphenylsulfone (I(50) = 5.8 x 10(-5) M) and 4-amino-4'-acetamidodiphenylsulfone (I(50) = 5.2 x 10(-5) M) were effective inhibitors o...

Being impermeable to folic acid, many bacteria must rely on their ability to synthesise folate from PABA, Pteridine, and glutamate in contrast the mammalian in cells cannot synthesise folic acid and must obtain preformed folate as a vitamin in their diet. The sulphonamides are structurally similar to PABA, the sulphonamides competitively inhibit dihydropteroate synthetase, the enzyme that catal...