title: Isolation and partial characterization of two minor glycoproteins from human erythrocyte membranes.
abstract: Two minor glycoproteins GP-II and GP-III, were isolated from human erythrocyte membranes and characterized chemically and immunologically. The chemical composition of GP-II and GP-III was similar: GP-II consisted of 81% protein and 19% carbohydrate of which 4.9% was hexose, 5.4% hexosamine and 7.8% sialic acid. GP-III consisted of 76% protein and 24% carbohydrate of which 7.6% was hexose, 7.2% hexosamine and 8.1% sialic acid. The amino acid composition of GP-II and GP-III was also similar. GP-II and GP-III, however, differed in chemical composition from the MN glycoprotein. GP-II and GP-III were associated with the blood group activities Ss, I and A, but not with the MN antigens. GP-III had higher blood group activities per mug of protein than did GP-II. The specific activities for the Ss blood group antigens were increased 3-10-fold by purificantion of GP-III from the aqueous phase of chloroform methanol extracts.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D001789:Blood Group Antigens; D001798:Blood Proteins / Q000032:analysis; D002241:Carbohydrates / Q000032:analysis; D002462:Cell Membrane / Q000032:analysis*; D004912:Erythrocytes / Q000032:analysis*; D006023:Glycoproteins / Q000097:blood* / Q000276:immunology; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D008970:Molecular Weight
chemical_list: D000596:Amino Acids; D001789:Blood Group Antigens; D001798:Blood Proteins; D002241:Carbohydrates; D006023:Glycoproteins