Identification of endogenous soluble glycoprotein receptors of bovine brain grey matter 14 kDa beta-galactoside-binding lectin.

The 14 kDa beta-galactoside-binding lectin from bovine brain grey matter (BBL) covalently attached to caproic acid-Sepharose by the N-hydroxy succinimide procedure was used to isolate endogenous glycoprotein receptors of this lectin. BBL-Sepharose could sugar-specifically retain several endogenous soluble glycoproteins with subunit molecular mass (in kDA) 44, 51, 60, 123 and 186. BBL, conjugated with horse radish peroxidase, could sugar-specifically recognize several glycoprotein subunits with molecular mass (in kDA) 58, 87, and 117 and 186 on Western blots. The only protein from an extract of bovine brain grey matter, that retained on Sepharose-immobilized endogenous N-linked glycoproteins and subsequently eluted with beta-galactosides was BBL as confirmed by electrophoresis and agglutination inhibition measurement. N-linked glycoproteins from bovine heart and even from human placenta were also efficient receptors of BBL. These results suggest that 14 kDa beta-galactoside-binding lectin is the major protein, if not the only one, that sugar-specifically interacts with endogenous soluble glycoproteins in bovine brain grey matter.