Comparison of kinetic parameters for acetylthiocholine, soman, ketamine and fasciculin towards acetylcholinesterase in liposomes and in solution.
Purified acetylcholinesterase from bovine brain was reconstituted by a detergent depletion technique into liposomes, prepared from soybean lecithin. The kinetics for the substrate acetylthiocholine and for three inhibitors with very different binding properties was studied. The results were compared with results from corresponding experiments with solubilized enzyme in detergent solution. The reconstituted enzyme showed a higher affinity for acetylthiocholine, ketamine and fasciculin. Parameters unaffected by the reconstitution were: turnover number for the substrate; the non-competitive component in ketamine inhibition and the kinetics for the active site-directed irreversible inhibitor soman.
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National Defence Research Establishment, Division of Experimental Medicine, Umeå, Sweden.
Koch
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D000110:Acetylcholinesterase / Q000378:metabolism*; D000122:Acetylthiocholine / Q000493:pharmacokinetics*; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D004546:Elapid Venoms / Q000494:pharmacology*; D007649:Ketamine / Q000494:pharmacology*; D008051:Lipid Bilayers; D008081:Liposomes; D012996:Solutions; D012999:Soman / Q000494:pharmacology*
D002800:Cholinesterase Inhibitors; D004546:Elapid Venoms; D008051:Lipid Bilayers; D008081:Liposomes; D012996:Solutions; D000122:Acetylthiocholine; D007649:Ketamine; C044937:fasciculin; D012999:Soman; D000110:Acetylcholinesterase