多粘蛋白的分离及其与纤粘蛋白的比较

用明胶、肝素和精氨酸亲和柱等从猪血浆中分离得到一明胶亲和蛋白Polynectin(PN)。此蛋白与精氨酸的亲和性很高,借此与FN分开,经聚丙烯酰胺凝胶电泳证明,PN的分子量为450 000,由多个相同的小亚基连接形成。免疫双扩散和ELISA结果表明,PN与FN之间无免疫交叉反应,PN只存在于猪血中,人及其它动物(牛、羊,小鼠和大鼠)血中无PN。PN不具有促中国地鼠卵巢(CHO)细胞贴壁活性。提示PN是一种不同于FN的大分子糖蛋白。此外,用无PN的FN免疫兔,制得高效价FN抗血清(1:32),并进一步纯化制得亲和层析纯FN抗体.

Isolation of Polynectin and Its Comparison with Fibronectin

A gelatin-binding protein polynectin (PN) was isolated from porcine plasma by affinity chromatography in sequence of columns of Sepharose 4B coupled with gelatin, arginine and heparin and then by gel filtration through Sephadex G-200. This protein was bound strongly to arginine column and thus could be seperated from fibronectin (FN). PN is similar to FN with respect to bind characteristics to affinity gels and with a molecular weight of about 450 000 in PAGE, PN being composed of several small su-bunits of the same molecular weight linked by disulfide bonds. Results of immunodiffusion and ELISA shows that: no immune reaction was observed between anti-PN antibody and FN and PN existed only in porcine plasma. but not in other animal (bovin, goat, mouse and rat) or human plasma. PN exhibited no cell-attachment-promoting effects on CHO cell. These indicate that PN was a glycoprotein different from FN. Moreover, a high titer (1:32) rabbit antiserum against porcine plasma FN (free from PN) was prepared from immunized rabbit, from which affinity purified anti-FN antibody was obtained through FN-Sepharose 4B column.