title: Modification of amino groups of human-erythrocyte glycoproteins and the new concept on the structural basis of M and M blood-group specificity.
abstract: 1. Various kinds of modification of amino groups of M and N blood group glycoproteins abolished their capacity to inhibit rabbit and human anti-M and anit-N sera. 2. The reversible modification of amino groups revealed that M and N blood group activity was restored after the removal of amino-group-blocking residues. 3. Modification of amino groups had an entirely different effect on the reactivity of red cell glycoproteins with Vicia graminea agglutinin. The serological activity of N glycoprotein towards Vicia graminea anti-N agglutinin was unchanged, whereas the weak activity of M glycoprotein towards this anti-N agglutinin was increased to the level of the of N glycoprotein. 4. These results indicate that there is a structural difference between M and N glycoproteins, which resides beyond the oligosaccharide chains. It suggests in turn that M and N blood group specificity is determined by amino acid sequence in the peptide chains of red cell glycoproteins.
mesh_terms: D000085:Acetates; D000595:Amino Acid Sequence; D000812:Anhydrides; D000818:Animals; D000937:Antigen-Antibody Reactions; D001665:Binding Sites; D001666:Binding Sites, Antibody; D002949:Citraconic Anhydrides; D004912:Erythrocytes / Q000032:analysis*; D006023:Glycoproteins; D006801:Humans; D037102:Lectins; D008951:MNSs Blood-Group System; D008298:Maleates; D009574:Nitro Compounds; D011485:Protein Binding; D011817:Rabbits / Q000276:immunology
chemical_list: D000085:Acetates; D000812:Anhydrides; D002949:Citraconic Anhydrides; D006023:Glycoproteins; D037102:Lectins; D008951:MNSs Blood-Group System; D008298:Maleates; D009574:Nitro Compounds