CYP78A1 preferentially expressed in developing inflorescences of Zea mays encoded a cytochrome P450-dependent lauric acid 12-monooxygenase.
Cytochrome P450 (P450 or CYP) monooxygenases play an important role in the oxidation of a number of lipophilic substrates including secondary metabolites in higher plants. Larkin reported that CYP78A1 was preferentially expressed in developing inflorescences of Zea mays (Larkin, Plant Mol. Biol. 25: 343-353, 1994). However, the enzymatic function of CYP78A1 hasn't been clarified yet. To characterized the enzymatic activity of CYP78A1, in this study, CYP78A1 cDNA and tobacco or yeast NADPH-cytochrome P450 oxidoreductase (P450 reductase) was expressed in the yeast Saccharomyces cerevisiae AH22 cells under the control of alcohol dehydrogenase promoter I and terminator. The reduced CO-difference spectrum of a microsomal fraction prepared from the transformed yeast cells expressing CYP78A1 and yeast P450 reductase showed a peak at 449 nm. Based on the spectrum, the content of a P450 molecule was estimated to be 45 pmol P450 equivalent/ mg of protein in the microsomal fraction. The recombinant yeast microsomes containing CYP78A1 and yeast P450 reductase were found to catalyze 12-monooxygenation of lauric acid. Based on these results, CYP78A1 preferentially expressed in developing inflorescences of Zea mays appeared to have participated in the monooxygenation of fatty acids.
Imaishi
H
H
Center for Cooperative Research and Development, Faculty of Agriculture, Kobe University, Japan.
Matsuo
S
S
Swai
E
E
Ohkawa
H
H
D002384:Catalysis; D042926:Cytochrome P-450 CYP4A; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism*; D018076:DNA, Complementary / Q000378:metabolism; D007850:Lauric Acids / Q000378:metabolism; D008861:Microsomes / Q000201:enzymology; D006899:Mixed Function Oxygenases / Q000096:biosynthesis* / Q000235:genetics; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D010940:Plant Proteins; D010947:Plants, Toxic; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D014026:Nicotiana / Q000201:enzymology; D003313:Zea mays / Q000201:enzymology*
D018076:DNA, Complementary; D007850:Lauric Acids; D010940:Plant Proteins; C030358:lauric acid; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; C088751:CYP78A1 protein, Zea mays; D042926:Cytochrome P-450 CYP4A; D009251:NADPH-Ferrihemoprotein Reductase