title: Molecular and biochemical characterization of juvenile hormone epoxide hydrolase from the silkworm, Bombyx mori.
abstract: One major route of insect juvenile hormone (JH) degradation is epoxide hydration by JH epoxide hydrolase (JHEH). A full-length cDNA (1536 bp) encoding a microsomal JHEH was isolated from the silkworm, Bombyx mori. Bommo-JHEH cDNA contains an open reading frame encoding a 461-amino acid protein (52 kDa), which reveals a high degree of similarity to the previously reported insect JHEHs. The residues Tyr298, Tyr373, and the HGWP motif corresponding to the oxyanion hole of JHEHs and the residues Asp227, His430, and Glu403 in the catalytic triad are well conserved in Bommo-JHEH. Bommo-JHEH was highly expressed in the fat body, where its mRNA expression pattern was in contrast to the pattern of hemolymph levels of JH during the larval development, suggesting that Bommo-JHEH plays an important role in JH degradation. Recombinant Bommo-JHEH (52 kDa) expressed in Sf9 insect cells was membrane-bound and had a high level of enzyme activity (300-fold over the control activity). This Bommo-JHEH study provides a better understanding of how JH levels are regulated in the domesticated silkworm.
authors.affiliation: Department of Molecular and Cell Biology, School of Life Science, University of Science and Technology of China, Hefei 230027, China.
authors.forename: Qi-Rui
authors.initials: QR
authors.lastname: Zhang
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Xu
authors.forename: Fu-Sheng
authors.initials: FS
authors.lastname: Chen
authors.forename: Sheng
authors.initials: S
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D012831:Bombyx / Q000201:enzymology* / Q000254:growth & development; D004851:Epoxide Hydrolases / Q000096:biosynthesis / Q000737:chemistry* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D007605:Juvenile Hormones / Q000378:metabolism; D007814:Larva / Q000201:enzymology / Q000254:growth & development; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000096:biosynthesis; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D007605:Juvenile Hormones; D011994:Recombinant Proteins; D004851:Epoxide Hydrolases; C055698:juvenile hormone epoxide hydrolase