摘要：

Blood-group antigens NN and Me-Vg were obtained as homogeneous substances from human red cells and meconium, respectively, and fully characterized chemically and biologically. For the first time a homogeneous erythrocyte membrane component of such high blood-group activity is described. Both substances induce anti-N specific antibodies in rabbits. They are also highly potent myxovirus receptors. The N and myxovirus specificities of the erythrocyte antigen are destroyed by sialidases and by proteases. Human N specificity is also destroyed by galactose oxidase. Specificities are carried by sialyl, sialylgalactopyranosyl, and β-galactopyranosyl structures. Both antigens are glycoproteins containing sialic acid, galactose, galactosamine, glucosamine, and mannose as the main carbohydrates. The Me-Vg antigen in addition contains a large amount of fucose. Components migrating on paper chromatograms like N,O-diacetylneuraminic acid have been identified in these antigens. This is the first account of these substances in products of human origin. The peptide part amounts to 44% in the NN antigen and to 13% in the Me-Vg antigen. Threonine and serine are prominent in both glycoproteins; the concentration of aromatic amino acids is low. Tryptophan and cystine are absent. Alkali degradation studies show that the threonine and serine are involved in the peptide-carbohydrate linkage; galactosamine and galactose are the carbohydrates destroyed by alkali in the NN antigen and glucosamine in addition in the antigen from meconium. Haptenic structures in which sialic acid and galactose predominate have been isolated by enzymatic and mild acid hydrolysis.

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