title: Molecular characterization of fatty acid alpha-hydroperoxide-forming enzyme (alpha-oxygenase) in rice plants.
abstract: Genes encoding an alpha-oxygenase, in Nicotiana tabacum and Arabidopsis thaliana, have been recently isolated. However, the reaction mechanism of the enzyme has not so far been elucidated. In this study, a cDNA encoding the fatty acid alpha-oxygenase gene in rice plants was isolated. The deduced amino acid sequence showed high similarity (63.6%) to that of N. tabacum. The gene was cloned into an expression vector system, pQE-30, and expressed in Escherichia coli as a host cell. Palmitic acid as a substrate was incubated with the lysate of the cells, and the products were analysed by HPLC. A compound formed predominantly by the recombinant enzyme was shown to be n-pentadecanal. By incubating the mixture at 0 degrees C, 2-hydroperoxypalmitic acid was detected as a primary product and little formation of n-pentadecanal was detected. Furthermore, uptake of molecular oxygen was observed with an oxygen electrode. This indicated that the gene in rice plants encodes the alpha-oxygenase.
authors.affiliation: Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Koeduka
authors.forename: K
authors.initials: K
authors.lastname: Matsui
authors.forename: Y
authors.initials: Y
authors.lastname: Akakabe
authors.forename: T
authors.initials: T
authors.lastname: Kajiwara
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D004926:Escherichia coli; D006801:Humans; D007527:Isoenzymes / Q000235:genetics; D008565:Membrane Proteins; D012275:Oryza / Q000201:enzymology* / Q000235:genetics*; D010105:Oxygenases / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins; D010947:Plants, Toxic; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics
chemical_list: D007527:Isoenzymes; D008565:Membrane Proteins; D010940:Plant Proteins; D011994:Recombinant Proteins; D010105:Oxygenases; C426838:fatty acid alpha-hydroperoxylase; C115355:pathogen-induced oxygenase, Nicotiana tabacum; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases