Lin J Y, Liu S Y
Toxicon. 1986;24(8):757-65. doi: 10.1016/0041-0101(86)90100-5.
Three toxic proteins and one agglutinin were purified from the seeds of Ricinus communis by a simple and fast method using Sepharose 4-B affinity chromatography followed by Sephadex G-100 gel filtration. The weakly adsorbed ricins A and B were retarded and eluted with the buffer from the affinity chromatographic column, while ricin C and ricinus agglutinin had to be eluted with 0.1 M galactose. The molecular weights of ricins A, B, and C were about 62,000 and that of ricinus agglutinin was 120,000, estimated by amino acid compositions and SDS gel electrophoresis. They all possessed two non-identical subunits: A and B chains linked by one disulfide bond. Their LD50 values were 4, 28, 14 and 112 micrograms per kg body weight of mice for ricins A, B and C and ricinus agglutinin, respectively. The amino acid compositions of the three toxins and their A and B subunits were very similar, but not identical, while ricinus agglutinin showed a different composition. Ricin A is a newly isolated lectin which has a strong inhibitory effect on the growth of tumor cells. By using cell cultures, it was demonstrated that the tumor cells were more sensitive to lectin than non-transformed cells, and that this could be caused by the higher binding affinity of lectin to tumor cells than to non-transformed cells.
通过一种简单快速的方法，利用琼脂糖4 - B亲和层析，随后进行葡聚糖凝胶G - 100凝胶过滤，从蓖麻种子中纯化出三种毒性蛋白和一种凝集素。弱吸附的蓖麻毒素A和B在亲和层析柱中被阻滞，并随缓冲液洗脱，而蓖麻毒素C和蓖麻凝集素则必须用0.1M半乳糖洗脱。根据氨基酸组成和SDS凝胶电泳估计，蓖麻毒素A、B和C的分子量约为62,000，蓖麻凝集素的分子量为120,000。它们都具有两个不同的亚基：通过一个二硫键连接的A链和B链。蓖麻毒素A、B和C以及蓖麻凝集素对小鼠的半数致死剂量（LD50）分别为每千克体重4、28、14和112微克。三种毒素及其A和B亚基的氨基酸组成非常相似，但不完全相同，而蓖麻凝集素显示出不同的组成。蓖麻毒素A是一种新分离的凝集素，对肿瘤细胞的生长具有强烈的抑制作用。通过细胞培养表明，肿瘤细胞比未转化细胞对凝集素更敏感，这可能是由于凝集素与肿瘤细胞的结合亲和力高于与未转化细胞的结合亲和力所致。
