Document Detail


Inhibition of Drosophila acetylcholinesterase by 7-(methylethoxyphosphinyloxy)1-methyl-quinolinium iodide.
MedLine Citation:
PMID:  10421448     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
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.
Authors:
J Stojan; V Marcel; D Fournier
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Chemico-biological interactions     Volume:  119-120     ISSN:  0009-2797     ISO Abbreviation:  Chem. Biol. Interact.     Publication Date:  1999 May 
Date Detail:
Created Date:  1999-08-19     Completed Date:  1999-08-19     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0227276     Medline TA:  Chem Biol Interact     Country:  IRELAND    
Other Details:
Languages:  eng     Pagination:  147-57     Citation Subset:  IM    
Affiliation:
Institute of Biochemistry, Medical Faculty, University of Ljubljana, Slovenia. stojan@ibmi.mf.uni-lj.si
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MeSH Terms
Descriptor/Qualifier:
Acetylcholinesterase / metabolism
Acetylthiocholine / metabolism
Animals
Brain / enzymology
Catalysis
Cholinesterase Inhibitors / pharmacokinetics,  pharmacology*
Drosophila melanogaster / enzymology*
Hydrolysis
Kinetics
Models, Chemical
Models, Molecular
Phosphorylation
Quinolinium Compounds / pharmacokinetics,  pharmacology*
Chemical
Reg. No./Substance:
0/Cholinesterase Inhibitors; 0/Quinolinium Compounds; 4468-05-7/Acetylthiocholine; 95230-44-7/7-((methylethoxyphosphinyl)oxy)-1-methylquinolinium; EC 3.1.1.7/Acetylcholinesterase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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