Collagen cell attachment protein from rat hepatoma cells.

This paper describes the isolation and partial characterization of a collagen cell attachment protein from the spent culture medium of rat hepatoma cells. When compared with serum fibronectin, this attachment protein differed in several biochemical parameters. The hepatoma attachment protein was partially purified by adsorbing and eluting from an inorganic gel, magnesium oxide. Cell adhesive activity may routinely recovered at levels of 10 to 30%, and a 2000-fold purification was attained. The hepatoma attachment protein was shown to be sensitive to trypsin and chymotrypsin, to be heat inactivated at 61 degrees, to have a molecular weight of 58,000, to have an isoelectric point of 4.1, to show an electrophoretic mobility on cellulose acetate of approximately one-half that of fibronectin, and not to cross-react with antifibronectin antisera.