Imaishi Hiromasa, Petkova-Andonova Mariana
Research Center for Environmental Genomics, Kobe University, Japan.
Biosci Biotechnol Biochem. 2007 Jan;71(1):104-13. doi: 10.1271/bbb.60396. Epub 2007 Jan 7.
A cDNA encoding a cytochrome P450 (CYP76B9) was isolated from Petunia hybrida. Northern blot analysis revealed preferential expression of the gene in flowers and leaves. The recombinant yeast microsomes expressing CYP76B9 was allowed to react with capric acid and lauric acid as substrates. One major metabolite was produced from each fatty acid after incubation with yeast microsomes expressing CYP76B9. The metabolites were identified by gas chromatography-mass spectrometry (GC-MS) as omega-hydroxy capric acid and omega-hydroxy lauric acid. The kinetic parameters of the reactions were Km=9.4 microM and Vmax=13.6 mol min(-1) per mol of P450 for capric acid, and Km=5.7 microM and Vmax=19.1 mol min(-1) per mol of P450 for lauric acid. We found that the omega-hydroxy metabolites of capric acid and lauric acid can affect the plant growth of Arabidopsis thaliana. Plants grown in the presence of omega-hydroxy fatty acids exhibited shorter root length than control plants with the corresponding non-hydroxylated fatty acids.
从矮牵牛中分离出一个编码细胞色素P450（CYP76B9）的cDNA。Northern印迹分析表明该基因在花和叶中优先表达。使表达CYP76B9的重组酵母微粒体与癸酸和月桂酸作为底物发生反应。在与表达CYP76B9的酵母微粒体孵育后，每种脂肪酸都产生了一种主要代谢物。通过气相色谱-质谱联用（GC-MS）将这些代谢物鉴定为ω-羟基癸酸和ω-羟基月桂酸。癸酸反应的动力学参数为Km = 9.4微摩尔，每摩尔P450的Vmax = 13.6摩尔·分钟⁻¹，月桂酸反应的动力学参数为Km = 5.7微摩尔，每摩尔P450的Vmax = 19.1摩尔·分钟⁻¹。我们发现癸酸和月桂酸的ω-羟基代谢物会影响拟南芥的植物生长。在ω-羟基脂肪酸存在下生长的植物，其根长比用相应的非羟基化脂肪酸处理的对照植物短。
