Wojtasek H, Prestwich G D
Department of Chemistry and Biochemistry, University at Stony Brook, New York 11794-3400, USA.
Biochem Biophys Res Commun. 1996 Mar 18;220(2):323-9. doi: 10.1006/bbrc.1996.0404.
We describe the first cDNA sequence encoding a juvenile hormone-specific epoxide hydrolase from an insect. A full-length cDNA clone revealed a 462-amino-acid open reading frame encoding an amino acid sequence with 44% identity and 64% similarity to human microsomal epoxide hydrolase. All residues in the catalytic triad (residues Asp227-His428-Asp350 in the M. sexta protein) were present, as was the conserved Trp154 corresponding to the oxyanion hole. The surprising similarity of insect juvenile hormone epoxide hydrolase to vertebrate microsomal epoxide hydrolases, coupled with the ancient lineage of the epoxide hydrolases and haloalkane dehalogenases, suggests that this catabolic enzyme evolved from an original ubiquitous detoxication function to a more recent role in hormonal regulation.
我们描述了首个来自昆虫的编码保幼激素特异性环氧化物水解酶的cDNA序列。一个全长cDNA克隆揭示了一个462个氨基酸的开放阅读框，其编码的氨基酸序列与人类微粒体环氧化物水解酶具有44%的同一性和64%的相似性。催化三联体中的所有残基（在烟草天蛾蛋白中为Asp227-His428-Asp350残基）均存在，对应于氧负离子洞的保守色氨酸Trp154也存在。昆虫保幼激素环氧化物水解酶与脊椎动物微粒体环氧化物水解酶惊人的相似性，再加上环氧化物水解酶和卤代烷脱卤酶的古老谱系，表明这种分解代谢酶从最初普遍存在的解毒功能进化到了最近在激素调节中的作用。
