Genes encoding an α-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 α-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 °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 α-oxygenase.
Molecular characterization of fatty acid α-hydroperoxide-forming enzyme (α-oxygenase) in rice plants
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T. Koeduka, K. Matsui, Y. Akakabe, T. Kajiwara; Molecular characterization of fatty acid α-hydroperoxide-forming enzyme (α-oxygenase) in rice plants. Biochem Soc Trans 1 December 2000; 28 (6): 765–768. doi: https://doi.org/10.1042/bst0280765
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