Separation of bovine heart galactose lectin from endogenous glycoproteins co-purified with the lectin during affinity chromatography

During affinity chromatographic purification of bovine heart 14 kDa galactose-binding lectin (galectin 1) on lactose-Sepharose, several high molecular weight non-lectin glycoproteins were co-purified with the lectin. Glycoprotein binding to the affinity matrix was neither hydrophobic nor ionic, but galactose-dependent since lactose abolished binding. Purification of galectin from the co-purified glycoproteins by affinity electrophoresis in presence of the specific sugar lactose increased agglutination activity about 65-fold, indicating that a complex containing galectin molecules bound sugar specifically to endogenous glycoproteins with sugar binding sites still available had been retained on lactose-Sepharose.