Studies on the specificity of rabbit hepatic carbohydrate-binding protein using neoglycoproteins

The binding of amidinoneoglycoproteins of bovine serum albumin to rabbit liver membranes was measured. Derivatives of bovine serum albumin to which equivalent amounts of beta-D-Gal, 6-O-Me-beta-D-Gal, beta-D-Fuc, alpha-L-Ara, beta-D-Glc, beta-D-Xyl, and beta-D-GalNAc had been attached bound to the membranes equally well. The attachment of alpha-D-Man, beta-L-Fuc, beta-D-GlcNAc, beta-D-allose, 3-O-Me-beta-D-Glc, and 2-deoxy-beta-D-Glc did not promote strong binding. The specificity of binding to the membranes was confirmed by measuring the binding of neoglycoproteins to the purified rabbit hepatic carbohydrate-binding protein immobilized on Sepharose 4B. The results indicate that, for binding, (1) neither the 6-OH (D-Fuc) nor the 5-CH2OH (L-Ara; D-Xyl) is required, (2) the 4-OH can be axial (D-Gal; L-Ara) or equatorial (D-Glc; D-Xyl), (3) the 3-OH must be equatorial (D-Glc) not axial (D-All) nor may it be substituted (3-O-Me-D-Glc), (4) the 2-OH must be equatorial (D-Glc) not axial (D-Man) and must be present (2-deoxy-D-Glc), and (5) the 2-OH can be replaced by an equatorial acetamido group if the 4-OH is axial (D-GalNAc) but not if it is equatorial (D-GlcNAc).