Primary Structure of the Oligosaccharide Determinant of Blood Group Cad Specificity

Glycophorin A and B from Cad erythrocyte membranes are the carriers of the blood group Cad determinants. They are characterized by a significant increase in molecular mass, as compared to the corresponding glycophorins from control erythrocytes (Cartron, J.-P., and Blanchard, D. (1982) Biochem. J. 207, 497-504). Lipid-free glycophorin A, purified from Cad red cells, showed an increased GalNAc content in comparison to blood group B, Cad-negative, control cells. Alkaline-borohydride treatment of this Cad glycophorin A released as a predominant species a pentasaccharide; its structure was determined, by methylation analysis and by 500-MHz 1H-NMR studies, to be: (formula; see text) This novel oligosaccharide inhibited strongly the hemagglutination of Cad erythrocytes by the Dolichos biflorus lectin. It shares with the blood group Sda determinant a terminal GalNAc beta (1 leads to 4)Gal beta (1 leads to .) sequence.