Argent R H, Roberts L M, Lord J M
Department of Biological Sciences, University of Warwick, Coventry, United Kingdom.
Biochem Biophys Res Commun. 1997 Dec 29;241(3):617-21. doi: 10.1006/bbrc.1997.7796.
[125I]-labeled ricin A chain was endocytosed by macrophages and Vero cells either on its own or as part of the ricin holotoxin. Subsequently [125I]-ricin A chain was recovered from intoxicated cells by immunoprecipitation or acetone precipitation. The recovered protein was shown to have the same electrophoretic mobility as the material supplied to the cells. These data challenge an earlier suggestion that limited intracellular processing of ricin A chain by proteolytic enzymes is required for maximal toxicity.
[125I]标记的蓖麻毒素A链可被巨噬细胞和非洲绿猴肾细胞单独内吞，也可作为蓖麻毒素全毒素的一部分被内吞。随后，通过免疫沉淀或丙酮沉淀从中毒细胞中回收[125I] - 蓖麻毒素A链。回收的蛋白质显示出与提供给细胞的物质相同的电泳迁移率。这些数据对早期的一种观点提出了挑战，即蓖麻毒素A链要发挥最大毒性需要蛋白水解酶对其进行有限的细胞内加工。
