Hicks C, Morré D J
Department of Medicinal Chemistry and Molecular Pharmacology, Hansen Life Sciences Research Building, Purdue University, West Lafayette, IN 47907, USA.
Biochim Biophys Acta. 1998 Oct 15;1375(1-2):1-5. doi: 10.1016/s0005-2736(98)00114-x.
Intact sections of soybean cut from regions of cell elongation of hypocotyls of etiolated soybean seedlings oxidized externally supplied NADH (NADH is an impermeant substrate). The oxidation of NADH by 1-cm intact sections was stimulated by the plant growth factor 2,4-dichlorophenoxyacetic acid (2,4-D). The optimum concentration of 2,4-D for stimulation was about 1 microM. Stimulations also were given by the naturally occurring 2,4-D analog, indole-3-acetic acid (IAA), but not by the growth inactive 2,4-D analog 2,3-dichlorophenoxyacetic acid (2,3-D). The findings confirm studies comparing inside-out and right side-out vesicles that show the 2,4-D-stimulated NADH oxidase to be located at the external cell surface. Since plant cells are unlikely to encounter NADH at their external cell surface, functions of the oxidase in reactions other than oxidation of NADH are discussed.
从黄化大豆幼苗下胚轴细胞伸长区域切下的完整大豆切片，能氧化外部提供的NADH（NADH是一种不能透过细胞膜的底物）。1厘米长的完整切片对NADH的氧化作用受到植物生长因子2,4 - 二氯苯氧乙酸（2,4 - D）的刺激。刺激作用的2,4 - D最佳浓度约为1微摩尔。天然存在的2,4 - D类似物吲哚 - 3 - 乙酸（IAA）也能产生刺激作用，但生长无活性的2,4 - D类似物2,3 - 二氯苯氧乙酸（2,3 - D）则不能。这些发现证实了对内外翻转囊泡和右侧向外囊泡的比较研究，表明2,4 - D刺激的NADH氧化酶位于细胞外表面。由于植物细胞在其细胞外表面不太可能遇到NADH，因此讨论了该氧化酶在除NADH氧化反应之外的其他反应中的功能。
