Damonte G, Sdraffa A, Zocchi E, Guida L, Polvani C, Tonetti M, Benatti U, Boquet P, De Flora A
Department of Biochemistry, University of Genoa, Italy.
Biochem Biophys Res Commun. 1990 Feb 14;166(3):1398-405. doi: 10.1016/0006-291x(90)91022-k.
Native membranes from human erythrocytes contain the following G proteins which are ADP-ribosylated by a number of bacterial toxins: Gi alpha and Go alpha (pertussis toxin), Gs alpha (cholera toxin), and three proteins of 27, 26 and 22 kDa (exoenzyme C3 from Clostridium botulinum). Three additional C3 substrates (18.5, 16.5 and 14.5 kDa) appeared in conditions of unrestrained proteolysis during hemolysis. SDS-PAGE separation of erythrocyte membrane proteins followed by electroblotting and incubation of nitrocellulose sheets with radiolabeled GTP revealed consistently four GTP-binding proteins with Mr values of 27, 26, 22 and 21 kDa. Although a 22 kDa protein was immunochemically identified as ras p21, the C3 substrate of 22 kDa is a different protein probably identifiable with a rho gene product. Accordingly, at least five distinct small molecular weight guanine nucleotide-binding proteins, whose functions are so far undetermined, are present in native human erythrocyte membranes.
来自人类红细胞的天然膜含有以下几种可被多种细菌毒素进行 ADP 核糖基化修饰的 G 蛋白：Giα 和 Goα（百日咳毒素）、Gsα（霍乱毒素），以及三种分子量分别为 27、26 和 22 kDa 的蛋白质（肉毒杆菌的外毒素 C3）。在溶血过程中无限制蛋白水解的条件下，出现了另外三种 C3 底物（分子量分别为 18.5、16.5 和 14.5 kDa）。对红细胞膜蛋白进行 SDS - PAGE 分离，随后进行电印迹，并将硝酸纤维素膜与放射性标记的 GTP 一起孵育，结果始终显示出四种分子量分别为 27、26、22 和 21 kDa 的 GTP 结合蛋白。尽管一种 22 kDa 的蛋白经免疫化学鉴定为 ras p21，但 22 kDa 的 C3 底物是一种不同的蛋白，可能与 rho 基因产物一致。因此，天然人类红细胞膜中存在至少五种功能尚未确定的不同的小分子鸟嘌呤核苷酸结合蛋白。
