Owen M J, Barber B H, Faulkes R A, Crumpton M J
Biochem J. 1980 Oct 15;192(1):49-57. doi: 10.1042/bj1920049.
Plasma-membrane preparations purified from pig lymphocytes contained a major polypeptide component of mol.wt. about 68 000. This component was identified as pig albumin by the following comparisons with authentic pig serum albumin: (a) co-migration when analysed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis under reducing and non-reducing conditions; (b) identical isoelectric points; (c) similar "fingerprints" of arginine-containing tryptic peptides; (d) reactivity with anti-(pig albumin) serum. The albumin was bound tightly to the plasma membrane. Biosynthetic labelling of pig lymphocytes under a variety of conditions failed to provide evidence that albumin was synthesized by lymphocytes, suggesting that the plasma-membrane-associated albumin was of extraneous origin. Radiolabelled pig serum albumin, however, failed to bind to the plasma-membrane fraction when added before cell disruption. Although lymphocyte plasma membrane preparations from other species possessed a polypeptide of about 68 000 mol.wt., this was judged not to be albumin on the basis of electrophoretic mobility under non-reducing conditions; also, no polypeptide was precipitated by anti-albumin sera. It is concluded that pig lymphocyte plasma-membrane preparations possess albumin which, although firmly attached, was probably of extraneous origin. This association appeared not to be common to lymphocytes from other species.
从猪淋巴细胞中纯化得到的质膜制剂含有一种主要的多肽成分，其分子量约为68000。通过与纯猪血清白蛋白进行以下比较，该成分被鉴定为猪白蛋白：(a) 在还原和非还原条件下，经十二烷基硫酸钠/聚丙烯酰胺凝胶电泳分析时共迁移；(b) 等电点相同；(c) 含精氨酸的胰蛋白酶肽的“指纹图谱”相似；(d) 与抗（猪白蛋白）血清反应。白蛋白紧密结合在质膜上。在各种条件下对猪淋巴细胞进行生物合成标记，均未能提供白蛋白由淋巴细胞合成的证据，这表明与质膜相关的白蛋白来源于外部。然而，在细胞破碎前加入放射性标记的猪血清白蛋白时，它未能与质膜部分结合。尽管来自其他物种的淋巴细胞质膜制剂含有一种分子量约为68000的多肽，但根据非还原条件下的电泳迁移率判断，该多肽不是白蛋白；此外，抗白蛋白血清也未沉淀出任何多肽。结论是，猪淋巴细胞质膜制剂含有白蛋白，尽管其紧密附着，但可能来源于外部。这种结合似乎并非其他物种淋巴细胞所共有。
