Kearns A, Whelan J, Young S, Elthon T E, Day D A
Division of Biochemistry and Molecular Biology, Faculty of Science, Australian National University, Canberra ACT 2601, Australia.
Plant Physiol. 1992 Jun;99(2):712-7. doi: 10.1104/pp.99.2.712.
Alternative oxidase activity (cyanide-insensitive respiration) was measured in mitochondria from the shoots, roots, and nodules of soybean (Glycine max L.) and siratro (Macroptilium atropurpureum) plants. Activity was highest in the shoots and lowest in the nodules. Alternative oxidase activity was associated with one (roots) or two (shoots) proteins between 30 and 35 kilodaltons that were detected by western blotting with a monoclonal antibody against Sauromatum guttatum alternative oxidase. No such protein was detected in nodule mitochondria. Measurements of oxygen uptake by isolated soybean root and nodule cells in the presence of cyanide and salicylhydroxamic acid indicated that alternative oxidase activity was confined to the uninfected cortex cells of the nodule. Immunoprecipitation of translation products of mRNA isolated from soybean shoots revealed a major band at 43 kilodaltons that is assumed to be the precursor of an alternative oxidase protein. This band was not seen when mRNA from nodules was treated in the same fashion. The results indicate that tissue-specific expression of the alternative oxidase occurs in soybean and siratro.
在大豆（Glycine max L.）和大翼豆（Macroptilium atropurpureum）植株的茎、根和根瘤的线粒体中测量了交替氧化酶活性（氰化物不敏感呼吸）。活性在茎中最高，在根瘤中最低。交替氧化酶活性与通过用抗天南星科植物交替氧化酶的单克隆抗体进行蛋白质印迹检测到的30至35千道尔顿之间的一种（根）或两种（茎）蛋白质相关。在根瘤线粒体中未检测到此类蛋白质。在氰化物和水杨基羟肟酸存在下对分离的大豆根和根瘤细胞的氧气摄取测量表明，交替氧化酶活性局限于根瘤未受感染的皮层细胞。对从大豆茎中分离的mRNA的翻译产物进行免疫沉淀，显示出一条43千道尔顿的主要条带，推测为交替氧化酶蛋白的前体。当以相同方式处理来自根瘤的mRNA时，未见到这条带。结果表明，交替氧化酶在大豆和大翼豆中存在组织特异性表达。
