title: Immunochemical properties of Mg erythrocytes.
abstract: The major erythrocyte membrane (MN) sialoglycoprotein in Mg red cells was found to exhibit a slightly decreased sodium-dodecyl-sulphate polyacrylamide gel electrophoretic molecular weight and periodic and/Schiff staining intensity. Mg antigen activity was shown to be associated with this molecule. As judged from chemical modification experiments, no carbohydrate but the glycoprotein's N-terminal amino acid is involved in the Mg receptor site. The endgroup of the glycoprotein was found to leucine and studies involving Staphylococcus aureus V8 protease suggest that a glutamic acid is located at the fifth position of its peptide chain. This indicates that the Mgs gene complex evolved from a mutation of an Ns allele. An amino acido substitution or deletion at the second, third and/or fourth position(s), preventing the glycosylation of all or some of these amino acids, provides an explanation for the properties of Mg erythrocytes.
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes; D004910:Erythrocyte Membrane / Q000276:immunology*; D004912:Erythrocytes / Q000276:immunology*; D006021:Glycophorins / Q000032:analysis / Q000276:immunology*; D006801:Humans; D008951:MNSs Blood-Group System / Q000235:genetics / Q000276:immunology*; D010503:Periodic Acid-Schiff Reaction; D012795:Sialoglycoproteins / Q000276:immunology*
chemical_list: D000939:Epitopes; D006021:Glycophorins; D008951:MNSs Blood-Group System; D012795:Sialoglycoproteins