Isolation and Partial Characterization of a ⁶⁷Ga-binding Glycoprotein from Morris 5123C Rat Hepatoma¹

A glycoprotein, particularly high in tumors, has been extracted from Morris 5123C rat hepatomas and purified. The compound constitutes a major binding component for ⁶⁷Ga in this hepatoma. It has a molecular weight of approximately 45,000. Its molecular weight was determined by sodium dodecyl sulfate:polyacrylamide gel electrophoresis and by Sephadex G-200 superfine gel filtration. The steps involved in its extraction and purification include ultrafiltration, gel filtration through Sephadex G-200 superfine, ion-exchange chromatography on diethylaminoethyl Sephadex A-50, and hydroxylapatite chromatography. The homogeneity of the compound was established by gel electrophoresis. The NH₂-terminal residue, the percentage of nitrogen, the nonamino carbohydrate content, and the amino acid composition are reported.