Remold-O'Donnell E
J Biol Chem. 1982 Jun 10;257(11):6600-4.
The biosynthetic origin was investigated of gp160, the trypsin- and plasmin-sensitive surface glycoprotein of caseinate-elicited macrophages from guinea pigs. Biosynthesized surface components were analyzed by reacting [35S]methionine-labeled macrophages with trinitrobenzene sulfonic acid and purifying trinitrophenyl-substituted surface proteins by immunoprecipitation. Identification of gp160 was based on its molecular weight and unique trypsin sensitivity. In addition, [35S]methionine-labeled surface and intracellular glycoproteins were purified by Lens culinaris lectin affinity chromatography. Both purification procedures demonstrated that gp160 is biosynthesized by elicited macrophages in culture. gp160 was first detected on the cell surface 60-80 min after pulse labeling; transit to the cell surface was almost maximal at 3 h. No evidence was found for intracellular accumulation of mature gp160, i.e. in time course experiments all [35S]methionine-labeled gp160 was sensitive to trypsin treatment of intact cells. However, [35S]methionine-labeled gp160 was not detected in pulse-labeled macrophages until 60 min of nonradioactive chase incubation, indicating the existence of a precursor form.
对豚鼠酪蛋白酸盐诱导的巨噬细胞中gp160（一种对胰蛋白酶和纤溶酶敏感的表面糖蛋白）的生物合成起源进行了研究。通过使[35S]甲硫氨酸标记的巨噬细胞与三硝基苯磺酸反应，并通过免疫沉淀纯化三硝基苯基取代的表面蛋白，来分析生物合成的表面成分。gp160的鉴定基于其分子量和独特的胰蛋白酶敏感性。此外，通过扁豆凝集素亲和层析纯化[35S]甲硫氨酸标记的表面糖蛋白和细胞内糖蛋白。两种纯化方法均表明，gp160是由培养的诱导巨噬细胞生物合成的。脉冲标记后60 - 80分钟，首次在细胞表面检测到gp160；3小时时向细胞表面的转运几乎达到最大值。未发现成熟gp160在细胞内积累的证据，即在时程实验中，所有[35S]甲硫氨酸标记的gp160对完整细胞的胰蛋白酶处理均敏感。然而，在脉冲标记的巨噬细胞中，直到非放射性追踪孵育60分钟后才检测到[35S]甲硫氨酸标记的gp160，这表明存在前体形式。
