title: Partial characterization of deltamethrin metabolism catalyzed by chymotrypsin.
abstract: Deltamethrin degradation was assessed by measuring deltamethrin reduction with GC-MS and UV-Vis spectrophotometry following incubation of various concentrations (4.96-24.80 microM) of deltamethrin with alpha-chymotrypsin from bovine pancreas. The retention times of crude products of deltamethrin metabolic reactions were 37.968 min, 37.415 min, 36.490 min, and 35.895 min. The UV-Vis spectrophotometric peak absorbance of deltamethrin was at 264 nm, and the peak absorbance of deltamethrin metabolic products were at 250 nm and 296 nm, respectively. Michaelis-Menten metabolic rate constants (V(max) and K(m)) were calculated by nonlinear regression for chymotrypsin using GraphPad Prism 4.0, the V(max) was 97.97+/-26.57 nmol/L/min and K(m) was 7.84+/-3.83 microM. The larvicidal bioassay tests indicated that the mixture from the degradation reaction showed LC(50) increased significantly (P<0.05). This is the first report demonstrating deltamethrin metabolism by chymotrypsin.
authors.affiliation: Department of Pathogen Biology, Key Laboratory of Modern Pathogen Biology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, Jiangsu Province, PR China.
authors.forename: Qinggui
authors.initials: Q
authors.lastname: Yang
authors.forename: Lixin
authors.initials: L
authors.lastname: Sun
authors.forename: Donghui
authors.initials: D
authors.lastname: Zhang
authors.forename: Jin
authors.initials: J
authors.lastname: Qian
authors.forename: Yan
authors.initials: Y
authors.lastname: Sun
authors.forename: Lei
authors.initials: L
authors.lastname: Ma
authors.forename: Jing
authors.initials: J
authors.lastname: Sun
authors.forename: Xiaobang
authors.initials: X
authors.lastname: Hu
authors.forename: Wenbin
authors.initials: W
authors.lastname: Tan
authors.forename: Weijie
authors.initials: W
authors.lastname: Wang
authors.forename: Changliang
authors.initials: C
authors.lastname: Zhu
mesh_terms: D000818:Animals; D002417:Cattle; D002918:Chymotrypsin / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D006868:Hydrolysis; D007306:Insecticides / Q000008:administration & dosage / Q000378:metabolism*; D007814:Larva / Q000187:drug effects; D007928:Lethal Dose 50; D009570:Nitriles / Q000008:administration & dosage / Q000378:metabolism*; D011722:Pyrethrins / Q000008:administration & dosage / Q000378:metabolism*; D012044:Regression Analysis; D013056:Spectrophotometry, Ultraviolet
chemical_list: D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; C017180:decamethrin; D002918:Chymotrypsin