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Inhibition of Drosophila acetylcholinesterase by 7-(methylethoxyphosphinyloxy)1-methyl-quinolinium iodide.
Stojan, J; Marcel, V; Fournier, D.
Afiliação
  • Stojan J; Institute of Biochemistry, Medical Faculty, University of Ljubljana, Slovenia. stojan@ibmi.mf.uni-lj.si
Chem Biol Interact ; 119-120: 147-57, 1999 May 14.
Article em En | MEDLINE | ID: mdl-10421448
The kinetic behaviour of Drosophila melanogaster acetylcholinesterase toward its substrate shows, in comparison with classic Michaelis-Menten kinetics, an apparent homotropic cooperative double activation-inhibition pattern. In order to construct an appropriate kinetic model and obtain further information on the mechanism of the catalytic action of this enzyme, the hydrolysis of acetylthiocholine in the absence and presence of different concentrations of synthetic quaternary methylphosphonate, 7-(methylethoxyphosphinyloxy)1-methyl-quinolinium iodide (MEPQ), was followed on a stopped-flow apparatus. The reaction at low substrate concentrations was followed until the change of the absorbance became negligible and at high concentrations only initial parts were recorded. A simultaneous analysis of the progress curves using numerical integration showed that the powerful organophosphonate inhibitor binds and compete with the substrate for the same binding sites. The results are also in accordance with the hypothesis that virtually every substrate or quasi-substrate molecule that enters into the gorge of active site is hydrolysed.
Assuntos
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Compostos de Quinolínio / Inibidores da Colinesterase / Drosophila melanogaster Limite: Animals Idioma: En Ano de publicação: 1999 Tipo de documento: Article
Buscar no Google
Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Compostos de Quinolínio / Inibidores da Colinesterase / Drosophila melanogaster Limite: Animals Idioma: En Ano de publicação: 1999 Tipo de documento: Article