Wang C, Croft KP, Jarlfors U, Hildebrand DF
Department of Agronomy (C.W., K.P.C.C., D.F.H.).
Plant Physiol. 1999 May;120(1):227-36. doi: 10.1104/pp.120.1.227.
Soybean (Glycine max) lipoxygenase (LOX) has been proposed to be involved in reserve lipid mobilization during germination. Here, subcellular fractionation studies show that LOX1, -2, -3, -4, -5, and -6 isozymes were associated with the soluble fraction but not with purified oil bodies. The purified oil bodies contained small amounts of LOX1 (<0.01% total activity), which apparently is an artifact of the purification process. Immunogold labeling indicated that, in cotyledon parenchyma cells of LOX wild-type seeds that had soaked and germinated for 4 d, the majority of LOX protein was present in the cytoplasm. In 4-d-germinated cotyledons of a LOX1/2/3 triple null mutant (L0), a small amount of label was found in the cytoplasm. In epidermal cells, LOX appeared in vacuoles of both wild-type and L0 germinated seeds. No LOXs cross-reacting with seed LOX antibodies were found to be associated with the cell wall, plasma membrane, oil bodies, or mitochondria. Lipid analysis showed that degradation rates of total lipids and triacylglycerols between the wild type and L0 were not significantly different. These results suggest that LOX1, -2, -3, -4, -5, and -6 are not directly involved in reserve lipid mobilization during soybean germination.
大豆（Glycine max）脂氧合酶（LOX）被认为参与种子萌发过程中的储备脂质动员。在此，亚细胞分级分离研究表明，LOX1、-2、-3、-4、-5和-6同工酶与可溶性部分相关，而与纯化的油体无关。纯化的油体含有少量的LOX1（<总活性的0.01%），这显然是纯化过程中的假象。免疫金标记表明，在浸泡并萌发4天的LOX野生型种子的子叶薄壁细胞中，大多数LOX蛋白存在于细胞质中。在LOX1/2/3三缺失突变体（L0）萌发4天的子叶中，在细胞质中发现少量标记。在表皮细胞中，LOX出现在野生型和L0萌发种子的液泡中。未发现与种子LOX抗体发生交叉反应的LOX与细胞壁、质膜、油体或线粒体相关。脂质分析表明，野生型和L0之间总脂质和三酰甘油的降解速率没有显著差异。这些结果表明，LOX1、-2、-3、-4、-5和-6不直接参与大豆萌发过程中的储备脂质动员。
