title: Selection of enzyme sources for improved sensitivity in enzymatic determination of organophosphorus pesticides.
abstract: The Michaelis-Menten constant (Km) for cholinesterases from different liver sources, the inhibitor concentration for 50% inhibition (I50), and the lower limit of estimation were determined for 3 organophosphorus pesticides and their oxygen analogs. Maximum sensitivity in organophosphorus pesticide determinations can be achieved by choosing the enzyme source which has a higher Km value. An inverse relationship is suggested between Km and the lower limit of estimation.
mesh_terms: D000818:Animals; D002800:Cholinesterase Inhibitors; D002802:Cholinesterases; D006736:Horses; D007306:Insecticides / Q000032:analysis* / Q000494:pharmacology; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D009943:Organophosphorus Compounds; D010573:Pesticide Residues / Q000032:analysis*; D051381:Rats; D012756:Sheep; D013045:Species Specificity; D013552:Swine
chemical_list: D002800:Cholinesterase Inhibitors; D007306:Insecticides; D009943:Organophosphorus Compounds; D010573:Pesticide Residues; D002802:Cholinesterases