title: Chemistry of human erythrocyte polylactosamine glycopeptides (erythroglycans) as related to ABH blood group antigenic determinants.
abstract: Human erythrocytes bear carbohydrates linked to both proteins and lipids. The majority of the carbohydrates is carried on two proteins: 1) Band 3 (which carries a high molecular weight polylactosamine, variously termed "Erythroglycan", "poly(glycosyl)peptide" or "lactosaminoglycan" and 2) Glycophorin A (which carries 15 O-linked tetrasaccharides and 1 triantennary N-linked structure). The remainder of carbohydrates are carried mainly by a few other glycoproteins (glycophorins B,C, the glucose transporter and others) with a minor amount carried by glycosphingolipids. This report concerns the Band 3 carbohydrate and its content of potential ABH-active sites. We have determined that an average number of two [Fuc1----2Ga11----4GlcNAc] sequences are carried by each "erythroglycan", polylactosamine N-linked oligosaccharide. One such large oligosaccharide occurs on each molecule of Band 3 polypeptide of which there are 1,000,000 copies per erythrocyte. Therefore, about 2,000,000 possible ABH sites are borne by Band 3 on each erythrocyte. This approximates the number of immunologically estimated ABH sites on human erythrocytes. Thus, Band 3 carbohydrate probably carries the majority of ABH substance on human red cells, while other glycoproteins and glycosphingolipids carry a minor fraction.
authors: Department of Biochemistry, Louisiana State University, Baton Rouge 70803.
authors: R A
authors: RA
authors: Laine
authors: J S
authors: JS
authors: Rush
mesh_terms: D000017:ABO Blood-Group System / Q000276:immunology*; D001457:Anion Exchange Protein 1, Erythrocyte / Q000276:immunology; D002240:Carbohydrate Sequence; D000939:Epitopes; D004912:Erythrocytes / Q000276:immunology; D006801:Humans; D008565:Membrane Proteins / Q000276:immunology*; D008969:Molecular Sequence Data; D008970:Molecular Weight
chemical_list: D000017:ABO Blood-Group System; D001457:Anion Exchange Protein 1, Erythrocyte; D000939:Epitopes; D008565:Membrane Proteins; C018059:erythroglycan