Isolation and characterization of Xenopus soluble epoxide hydrolase

• Published in: Biochimica et biophysica acta 2014-07, Vol.1841 (7), p.954-962
• Main Authors: Purba, Endang R., Oguro, Ami, Imaoka, Susumu
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amino Acid Substitution; Amphibian Proteins - genetics; Amphibian Proteins - isolation & purification; Amphibian Proteins - metabolism; Animals; Cloning, Molecular; DNA, Complementary - genetics; DNA, Complementary - metabolism; Embryo, Nonmammalian; Epoxide Hydrolases - genetics; Epoxide Hydrolases - isolation & purification; Epoxide Hydrolases - metabolism; Epoxyeicosatrienoic acid; Escherichia coli - genetics; Escherichia coli - metabolism; Gene Expression; Hymecromone - analogs & derivatives; Kinetics; Lysophospholipids; Molecular Sequence Data; Mutation; Phosphatase; Phosphoric Monoester Hydrolases - metabolism; Sequence Alignment; Sequence Homology, Amino Acid; Solubility; Soluble epoxide hydrolase; Species Specificity; Substrate Specificity; Xenopus laevis; Xenopus laevis - embryology; Xenopus laevis - genetics; Xenopus laevis - metabolism
• ISSN: 1388-1981; 0006-3002; 1879-2618
• DOI: 10.1016/j.bbalip.2014.03.010

Soluble epoxide hydrolase (sEH) contributes to cell growth, but the contribution of sEH to embryonic development is not well understood. In this study, Xenopus sEH cDNA was isolated from embryos of Xenopus laevis. The Xenopus sEH was expressed in Escherichia coli and was purified. The epoxide hydrolase and phosphatase activities of purified sEH were investigated. The Xenopus sEH did not show phosphatase activity toward 4-methylumbelliferyl phosphate or several lysophosphatidic acids although it had EH activity. The amino acid sequence of Xenopus sEH was compared with that reported previously. We found amino acid substitutions of the 29th Thr to Asn and the 146th Arg to His and prepared a sEH mutant (N29T/H146R), designed as mutant 1. Neither wild-type sEH nor mutant 1 had phosphatase activity. Additional substitution of the 11th Gly with Asp was found by comparison with human sEH which has phosphatase activity, but the Xenopus sEH mutant G11D prepared as mutant 2 did not have phosphatase activity. The epoxide hydrolase activity of sEH seemed to be similar to that of human sEH, while Xenopus sEH did not have phosphatase activity toward several substrates that human sEH metabolizes. •Xenopus sEH had EH activity, and its activity was similar to that of humans.•Xenopus sEH had no phosphatase activity toward human's phosphatase substrates.•EETs, endogenous substrates of sEH, were detected in Xenopus liver.•sEH levels were increased with the development of Xenopus embryos.