Department of Biology, University of California, Los Angeles, Los Angeles, California 90024.
Plant Physiol. 1986 Apr;80(4):950-5. doi: 10.1104/pp.80.4.950.
The matrix of glyoxysomes from endosperm of castor bean (Ricinus communis cv Hale) seedlings has been analyzed for the presence of glycosylated proteins. Glyoxysome preparations were monitored for organelle homogeneity by electron microscopy and enzyme marker activities. Glyoxysomes were essentially free of endoplasmic reticulum, mitochondria, and protein bodies. At least eight glyoxysomal matrix glycopeptides ranging in size from 39 to 160 kilodaltons were identified by their affinity for concanavalin A. The glyoxysomal glycoproteins were shown to be radioactively labeled when endosperm was allowed to incorporate glucosamine. Incorporation of glucosamine was inhibited by tunicamycin under conditions which did not inhibit protein synthesis. Hydrolysis of glyoxysomal extracts and subsequent analysis by paper chromatography showed that the labeled precursor was incorporated into the glycoprotein without prior dispersion of the label into amino acids. The present data demonstrate the occurrence of N-linked, high mannose oligosaccharides on polypeptides of the glyoxysomal matrix. This finding is discussed in relation to pathways of protein maturation and transport during glyoxysomal biogenesis.
蓖麻种子（Ricinus communis cv Hale）胚乳的乙醛酸体基质已被分析是否存在糖基化蛋白。通过电子显微镜和酶标记活性监测乙醛酸体制剂以确保细胞器的均一性。乙醛酸体基本上不含内质网、线粒体和蛋白体。通过其对刀豆球蛋白 A 的亲和力，鉴定了大小在 39 至 160 千道尔顿之间的至少八种乙醛酸体基质糖肽。当胚乳允许掺入葡萄糖胺时，显示出乙醛酸体糖蛋白被放射性标记。在不抑制蛋白质合成的条件下，使用衣霉素抑制葡萄糖胺的掺入。水解乙醛酸体提取物并随后通过纸层析分析表明，标记前体在不将标记物分散成氨基酸的情况下掺入糖蛋白中。目前的数据表明，在乙醛酸体基质的多肽上存在 N-连接的高甘露糖寡糖。这一发现与乙醛酸体生物发生过程中蛋白质成熟和运输的途径有关。
