[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 separated 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 subunits 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 (bovine, 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.