Yun Min-Soo, Chen Weijun, Deng Fan, Yogo Yasuhiro
Upland Weed Laboratory, Department of Field Environment, National Agricultural Research Centre, 3-1-1 Kannondai, Tsukuba, Ibaraki 305-8666, Japan.
Pest Manag Sci. 2007 Aug;63(8):815-20. doi: 10.1002/ps.1404.
4-Coumarate:CoA ligase (4CL, EC 6.2.1.12) in the phenylpropanoid pathway in plants has attracted interest as a novel target for developing effective plant growth inhibitors (PGIs). In a previous study in which the 4CL inhibitory activity of 28 existing herbicides was investigated using an optimized in vitro screening assay, 4CL activity was found to be strongly inhibited by propanil and swep at 100 microM. Here, further experimental evidence is provided to substantiate the previous result. Using 4-coumaric acid as substrate, tobacco 4CL activity was inhibited by propanil or swep in a concentration-dependent manner, with 50% inhibition concentrations (I(50)) of 39.6 and 6 microM respectively. These herbicides also exhibited uncompetitive inhibition towards 4-coumaric acid. Furthermore, 4CLs from several plant species were inhibited by the herbicides within a range from 1 to 50 microM. It is proposed that these herbicides have another site of action as a result of the inhibition of 4CL in the phenylpropanoid pathway, and this enzyme represents a new target site for the development of PGI.
4-香豆酸：辅酶A连接酶（4CL，EC 6.2.1.12）存在于植物的苯丙烷类代谢途径中，作为开发有效植物生长抑制剂（PGIs）的新靶点受到关注。在之前的一项研究中，使用优化的体外筛选试验研究了28种现有除草剂的4CL抑制活性，发现丙酯草醚和灭草猛在100微摩尔浓度下能强烈抑制4CL活性。在此，提供进一步的实验证据来证实先前的结果。以4-香豆酸为底物，丙酯草醚或灭草猛对烟草4CL活性呈浓度依赖性抑制，其50%抑制浓度（I(50)）分别为39.6微摩尔和6微摩尔。这些除草剂对4-香豆酸还表现出非竞争性抑制。此外，几种植物物种的4CL在1至50微摩尔浓度范围内被这些除草剂抑制。研究表明，由于这些除草剂抑制了苯丙烷类代谢途径中的4CL，它们具有另一个作用位点，并且这种酶代表了开发PGIs的新靶点。
