Marcel_2000_J.Biol.Chem_275_11603

Reference

Title : Exploration of the Drosophila acetylcholinesterase substrate activation site using a reversible inhibitor (Triton X-100) and mutated enzymes - Marcel_2000_J.Biol.Chem_275_11603
Author(s) : Marcel V , Estrada-Mondaca S , Magne F , Stojan J , Klaebe A , Fournier D
Ref : Journal of Biological Chemistry , 275 :11603 , 2000
Abstract :

Cholinesterases are activated at low substrate concentration, and this is followed by inhibition as the level of substrate increases. However, one of these two components is sometimes lacking. In Drosophila acetylcholinesterase, the two phases are present, allowing both phenomena to be studied. Several kinetic schemes can explain this complex kinetic behavior. Among them, one model assumes that activation results from the binding of a substrate molecule to a non-productive site affecting the entrance of a substrate molecule into the active site. To test this hypothesis, we looked for an inhibitor competitive for activation and we found Triton X-100. Using organophosphates or carbamates as hemisubstrates, we showed that Triton X-100 inhibits or increases phosphorylation or carbamoylation of the enzyme. In vitro mutagenesis of the residues lining the active site gorge allowed us to locate the Triton X-100 binding site at the rim of the gorge with glutamate 107 playing the major role. These results led to the hypothesis that substrate binding at this site affects the entrance of another substrate molecule into the active site cleft.

PubMedSearch : Marcel_2000_J.Biol.Chem_275_11603
PubMedID: 10766776

Citations formats

Marcel V, Estrada-Mondaca S, Magne F, Stojan J, Klaebe A, Fournier D (2000)
Exploration of the Drosophila acetylcholinesterase substrate activation site using a reversible inhibitor (Triton X-100) and mutated enzymes
Journal of Biological Chemistry 275 :11603

Marcel V, Estrada-Mondaca S, Magne F, Stojan J, Klaebe A, Fournier D (2000)
Journal of Biological Chemistry 275 :11603