Tranbarger T J, Franceschi V R, Hildebrand D F, Grimes H D
Department of Botany, Washington State University, Pullman 99164-4238.
Plant Cell. 1991 Sep;3(9):973-87. doi: 10.1105/tpc.3.9.973.
Soybean leaves contain three proteins (the vegetative storage proteins or VSPs) that respond to nitrogen status and are believed to be involved in the temporary storage of nitrogen. One of these proteins, with a molecular mass of 94 kD and termed vsp94, was microsequenced. Partial amino acid sequence indicated that vsp94 was highly homologous to the lipoxygenase protein family. Further evidence that vsp94 is a lipoxygenase was obtained by demonstrating that vsp94 cross-reacted with a lipoxygenase antibody. Also, a lipoxygenase cDNA coding region was able to detect changes in an mRNA that closely parallel changes in vsp94 protein levels resulting from alteration of nitrogen sinks. Extensive immunocytochemical data indicate that this vsp94/lipoxygenase is primarily expressed in the paraveinal mesophyll cells and is subcellularly localized in the vacuole. These observations are significant in that they suggest that plant lipoxygenases may be bifunctional proteins able to function enzymatically in the hydroperoxidation of lipids and also to serve a role in the temporary storage of nitrogen during vegetative growth.
大豆叶片含有三种蛋白质（营养贮藏蛋白或VSPs），它们对氮素状况有响应，并且被认为参与氮的临时贮藏。其中一种蛋白质，分子量为94 kD，称为vsp94，已进行了微量测序。部分氨基酸序列表明，vsp94与脂氧合酶蛋白家族高度同源。通过证明vsp94与脂氧合酶抗体发生交叉反应，获得了vsp94是一种脂氧合酶的进一步证据。此外，一个脂氧合酶cDNA编码区能够检测到一种mRNA的变化，该变化与氮库改变导致的vsp94蛋白水平变化密切平行。大量免疫细胞化学数据表明，这种vsp94/脂氧合酶主要在脉间叶肉细胞中表达，并且在亚细胞水平上定位于液泡中。这些观察结果具有重要意义，因为它们表明植物脂氧合酶可能是双功能蛋白，能够在脂质的氢过氧化反应中发挥酶促作用，并且在营养生长期间也能在氮的临时贮藏中发挥作用。
