Examination of intrinsic sulfonamide resistance in Bacillus anthracis: a novel assay for dihydropteroate synthase.
Biochim Biophys Acta
; 1780(5): 848-53, 2008 May.
Article
em En
| MEDLINE
| ID: mdl-18342015
ABSTRACT
Dihydropteroate synthase (DHPS) catalyzes the formation of dihydropteroate and Mg-pyrophosphate from 6-hydroxymethyl-7,8-dihydropterin diphosphate and para-aminobenzoic acid. The Bacillus anthracis DHPS is intrinsically resistant to sulfonamides. However, using a radioassay that monitors the dihydropteroate product, the enzyme was inhibited by the same sulfonamides. A continuous spectrophotometric assay for measuring the enzymatic activity of DHPS was developed and used to examine the effects of sulfonamides on the enzyme. The new assay couples the production of MgPPi to the pyrophosphate-dependent phosphofructokinase/aldolase/triose isomerase/alpha-glycerophosphate dehydrogenase reactions and monitors the disappearance of NADH at 340nm. The coupled enzyme assay demonstrates that resistance of the B. anthracis DHPS results in part from the use of the sulfonamides as alternative substrates, resulting in the formation of sulfonamide-pterin adducts, and not necessarily due to an inability to bind them.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sulfonamidas
/
Bacillus anthracis
/
Farmacorresistência Bacteriana
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
2008
Tipo de documento:
Article
País de afiliação:
Estados Unidos