title: Characterization of pyrethroid hydrolysis by the human liver carboxylesterases hCE-1 and hCE-2.
abstract: Carboxylesterases hydrolyze a large array of endogenous and exogenous ester-containing compounds, including pyrethroid insecticides. Herein, we report the specific activities and kinetic parameters of human carboxylesterase (hCE)-1 and hCE-2 using authentic pyrethroids and pyrethroid-like, fluorescent surrogates. Both hCE-1 and hCE-2 hydrolyzed type I and II pyrethroids with strong stereoselectivity. For example, the trans-isomers of permethrin and cypermethrin were hydrolyzed much faster than corresponding cis-counterparts by both enzymes. Kinetic values of hCE-1 and hCE-2 were determined using cypermethrin and 11 stereoisomers of the pyrethroid-like, fluorescent surrogates. K(m) values for the authentic pyrethroids and fluorescent surrogates were in general lower than those for other ester-containing substrates of hCEs. The pyrethroid-like, fluorescent surrogates were hydrolyzed at rates similar to the authentic pyrethroids by both enzymes, suggesting the potential of these compounds as tools for high throughput screening of esterases that hydrolyze pyrethroids.
authors.affiliation: Department of Entomology and UC Davis Cancer Center, University of California, Davis, CA 95616, USA.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Nishi
authors.forename: Huazhang
authors.initials: H
authors.lastname: Huang
authors.forename: Shizuo G
authors.initials: SG
authors.lastname: Kamita
authors.forename: In-Hae
authors.initials: IH
authors.lastname: Kim
authors.forename: Christophe
authors.initials: C
authors.lastname: Morisseau
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Hammock
mesh_terms: D002265:Carboxylic Ester Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D005456:Fluorescent Dyes / Q000737:chemistry; D015723:Gene Library; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D011722:Pyrethrins / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D013237:Stereoisomerism
chemical_list: D005456:Fluorescent Dyes; D011722:Pyrethrins; D011994:Recombinant Proteins; C017160:cypermethrin; D002265:Carboxylic Ester Hydrolases; C474609:CES1 protein, human