title: Identification of a diazinon-metabolizing glutathione S-transferase in the silkworm, Bombyx mori.
abstract: The glutathione S-transferase superfamily play key roles in the metabolism of numerous xenobiotics. We report herein the identification and characterization of a novel glutathione S-transferase in the silkworm, Bombyx mori. The enzyme (bmGSTu2) conjugates glutathione to 1-chloro-2,4-dinitrobenzene, as well as metabolizing diazinon, one of the organophosphate insecticides. Quantitative reverse transcription-polymerase chain reaction analysis of transcripts demonstrated that bmGSTu2 expression was induced 1.7-fold in a resistant strain of B. mori. Mutagenesis of putative amino acid residues in the glutathione-binding site revealed that Ile54, Glu66, Ser67, and Asn68 are crucial for enzymatic function. These results provide insights into the catalysis of glutathione conjugation in silkworm by bmGSTu2 and into the detoxification of organophosphate insecticides.
authors.affiliation: Department of Bioscience and Biotechnology, Kyushu University Graduate School, Fukuoka, Japan.
authors.forename: Kohji
authors.initials: K
authors.lastname: Yamamoto
authors.affiliation: Department of Bioscience and Biotechnology, Kyushu University Graduate School, Fukuoka, Japan.
authors.forename: Naotaka
authors.initials: N
authors.lastname: Yamada
mesh_terms: D000818:Animals; D001665:Binding Sites; D001711:Biotransformation; D012831:Bombyx / Q000201:enzymology*; D004252:DNA Mutational Analysis; D003976:Diazinon / Q000378:metabolism*; D004137:Dinitrochlorobenzene / Q000378:metabolism; D020869:Gene Expression Profiling; D005978:Glutathione / Q000378:metabolism; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism*; D007306:Insecticides / Q000378:metabolism*
chemical_list: D004137:Dinitrochlorobenzene; D007306:Insecticides; D005982:Glutathione Transferase; D005978:Glutathione; D003976:Diazinon