Identification of blood group A-active glycoproteins in the human erythrocyte membrane.
Normal human erythrocytes of blood groups A1, A2, B and O, and En (a-) erythrocytes lacking glycophorin A, but with A1B-activity, were surface-labeled with tritiated sodium borohydride after oxidation of terminal galactosyl and N-acetylgalactosaminyl residues with galactose oxidase. A1 cells were also labeled by lactoperoxidase catalyzed iodination. After solubilization in Triton X-100, the blood group A-active glycoconjugates were isolated using the A-specific lectin from Vicia cracca coupled to Sepharose. No radioactivity was bound from erythrocytes of B and O blood groups. The glycoconjugates from A cell membranes which bound to the lectin and were eluted with 0.01 M N-acetyl-D-galactosamine were analyzed using cylindrical or slab gel electrophoresis in the presence of sodium dodecyl sulfate. The A-active glycoproteins included the major integral glycoprotein, band 3, and many minor, previously poorly defined components. Glycophorins A and B did not contain A-activity.
D000017:ABO Blood-Group System / Q000276:immunology*; D004910:Erythrocyte Membrane / Q000276:immunology*; D004912:Erythrocytes / Q000276:immunology*; D006023:Glycoproteins / Q000097:blood / Q000276:immunology*; D006801:Humans; D037102:Lectins / Q000276:immunology; D008970:Molecular Weight
D000017:ABO Blood-Group System; D006023:Glycoproteins; D037102:Lectins