title: Characterization of acetylcholinesterase from elm left beetle, Xanthogaleruca luteola and QSAR of temephos derivatives against its activity.
abstract: Insect acetylcholinesterase (AChE) is the principal target for organophosphate (OP) and carbamate (CB) insecticides. In this research, an AChE from third instar larvae of elm left beetle, Xanthogaleruca luteola was purified by affinity chromatography. The enzyme was purified 75.29-fold with a total yield of 8.51%. As shown on denaturing SDS-PAGE, the molecular mass of purified AChE was 70kDa. The enzyme demonstrated maximum activity at pH7 and 35°C. Furthermore, a series of temephos (Tem) derivatives with the general structure of P(O)XP(O) (1-44) were prepared, synthesized and characterized by31P,13C,1H NMR and FT-IR spectral techniques. The toxicity of 36 new Tem derivatives was screened on the third instar larvae and the compound compound 1,2 cyclohexane-N,N'-bis(N,N'-piperidine phosphoramidate) exhibited the highest insecticidal potential. The method of kinetic analysis is applied in order to obtain the maximum velocity (Vmax), the Michaelis constant (Km) and the parameters characterizing the inhibition type for inhibitors with >75% mortality in preliminary bioassay. The inhibition mechanism was mixed and inhibitory constant (Ki) was calculated as 4.70μM-1min-1for this compound. Quantitative structure-activity relationship (QSAR) equations of these compounds indicated that the electron orbital energy has major effect on insecticidal properties.
authors.affiliation: Department of Plant Protection, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran.
authors.forename: Mahboobeh
authors.initials: M
authors.lastname: Sharifi
authors.affiliation: Department of Plant Protection, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran. Electronic address: ghadamyari@guilan.ac.ir.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ghadamyari
authors.affiliation: Department of Chemistry, Tarbiat Modares University, Tehran, Iran.
authors.forename: Khodayar
authors.initials: K
authors.lastname: Gholivand
authors.affiliation: Department of Chemistry, Tarbiat Modares University, Tehran, Iran.
authors.forename: Ali Asghar Ebrahimi
authors.initials: AAE
authors.lastname: Valmoozi
authors.affiliation: Department of Biochemistry, Tarbiat Modares University, Tehran, Iran.
authors.forename: Reza H
authors.initials: RH
authors.lastname: Sajedi
mesh_terms: D000110:Acetylcholinesterase / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D001517:Coleoptera / Q000201:enzymology*; D019476:Insect Proteins / Q000302:isolation & purification / Q000378:metabolism*; D007306:Insecticides / Q000737:chemistry / Q000494:pharmacology*; D007814:Larva / Q000201:enzymology; D021281:Quantitative Structure-Activity Relationship; D000002:Temefos / Q000031:analogs & derivatives / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D002800:Cholinesterase Inhibitors; D019476:Insect Proteins; D007306:Insecticides; D000110:Acetylcholinesterase; D000002:Temefos
keywords: Acetylcholinesterase; Biochemical properties; Organophosphate; QSAR