Inhibition of recombinant Pneumocystis carinii dihydropteroate synthetase by sulfa drugs.

Article Details

Citation

Hong YL, Hossler PA, Calhoun DH, Meshnick SR

Inhibition of recombinant Pneumocystis carinii dihydropteroate synthetase by sulfa drugs.

Antimicrob Agents Chemother. 1995 Aug;39(8):1756-63.

PubMed ID
7486915 [ View in PubMed
]
Abstract

Forty-four sulfa drugs were screened against crude preparations of recombinant Pneumocystis carinii dihydropteroate synthetase. The apparent Michaelis-Menten constants (Km) for p-aminobenzoic acid and 7,8-dihydro-6-hydroxymethylpterin pyrophosphate were 0.34 +/- 0.02 and 2.50 +/- 0.71 microM, respectively. Several sulfa drugs, including sulfathiazole, sulfachlorpyridazine, sulfamethoxypyridazine, and sulfathiourea, inhibited dihydropteroate synthetase approximately as well as sulfamethoxazole, as determined by the concentrations which cause 50% inhibition and/or by Ki. For all sulfones and sulfonamides tested, unsubstituted p-amino groups were necessary for activity, and sulfonamides containing an N1-heterocyclic substituent were found to be the most effective inhibitors. Folate biosynthesis in isolated intact P. carinii was approximately equally sensitive to inhibition by sulfamethoxazole, sulfachlorpyridazine, sulfamethoxypyridazine, sulfisoxazole, and sulfathiazole. Two of these drugs, sulfamethoxypyridazine and sulfisoxazole, are known to be less toxic than sulfamethoxazole and should be further evaluated for the treatment of P. carinii pneumonia.

DrugBank Data that Cites this Article

Drug Targets
DrugTargetKindOrganismPharmacological ActionActions
Acetyl sulfisoxazoleDihydropteroate synthaseProteinEscherichia coli (strain K12)
Yes
Inhibitor
Details
SulfamerazineDihydropteroate synthaseProteinEscherichia coli (strain K12)
Yes
Inhibitor
Details
SulfamethazineDihydropteroate synthaseProteinEscherichia coli (strain K12)
Yes
Inhibitor
Details
SulfaphenazoleDihydropteroate synthaseProteinEscherichia coli (strain K12)
Yes
Inhibitor
Details
SulfisoxazoleDihydropteroate synthaseProteinEscherichia coli (strain K12)
Yes
Inhibitor
Details