Properties of the membrane proteins of rat liver lysosomes. The majority of lysosomal membrane proteins are exposed to the cytoplasm.
Properties of the membrane proteins of rat liver lysosomes. The majority of lysosomal membrane proteins are exposed to the cytoplasm.
复制标题
大鼠肝溶酶体膜蛋白的特性。
作者：
D. Schneider;J. Burnside;F. Gorga;C. Nettleton
将大鼠肝脏溶酶体裂解并通过 0.2M-NaCl 差速离心进行亚分级，产生膜状沉淀。该膜级分含有低于 20% 的溶酶体蛋白、每毫克蛋白质约 1.2μmol/min 的三磷酸腺苷酶活性、每毫克蛋白质 120nmol 的硫醇基团以及在十二烷基硫酸钠/聚丙烯酰胺凝胶电泳上至少有 16 个蛋白质和糖蛋白条带。用（1）[125I]碘过氧化氢-乳过氧化物酶、（2）甲苯2,4-二异氰酸酯激活的牛血清白蛋白、（3）胰蛋白酶和（4）枯草杆菌蛋白酶处理后从溶酶体分离的膜的凝胶模式表明大多数膜蛋白暴露于细胞质。这些暴露的蛋白质是细胞内受体的候选者，其识别待降解的物质或含有这些物质的囊泡。
Rat liver lysosomes were lysed and subfractionated by differential centrifugation through 0.2M-NaCl to yield a membranous pellet. This membrane fraction contains less than 20% of the lysosomal protein, adenosine triphosphatase activity of about 1.2mumol/min per mg of protein, 120nmol of thiol groups/mg of protein and at least 16 protein and glycoprotein bands on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The gel patterns of membranes isolated from lysosomes after treatment with (1) [125I]iodidehydrogen peroxide-lactoperoxidase, (2) toluene 2,4-di-isocyanate-activated bovine serum albumin, (3) trypsin and (4) subtilisin indicate that most of the membrane proteins are exposed to the cytoplasm. These exposed proteins are candidates for intracellular receptors which recognize either substances that are to be degraded or vesicles containing those substances.