title: Primary structure of N-glycosidically linked asialoglycans of secretory immunoglobulins A from human milk.
abstract: The asialoglycopeptides obtained from secretory immunoglobulins A from human milk have been separated by gel filtration and affinity chromatography on Concanavalin A-Sepharose and Lens culinaris agglutinin-Sepharose columns. Their structures have been determined by sugar analysis, methylation studies including mass spectrometry and 500-MHz 1H-NMR spectroscopy. The glycans are of the biantennary N-acetyllactosamine type differing in their degree of extension by fucosyl-N-acetyllactosamine residues. The overall structures of the glycopeptides are as follows: (Formula: see text) Most of the asialoglycopeptide structures possess an intersecting GlcNAc residue; they are suggested to be located on the alpha chain of the secretory immunoglobulins A of human milk. The non-intersected structures probably occur on the secretory piece. The methodology applied to the structural analysis adequately coped with the extremely high degree of heterogeneity shown by the structures.
mesh_terms: D002241:Carbohydrates / Q000032:analysis; D055598:Chemical Phenomena; D002621:Chemistry; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D005260:Female; D006020:Glycopeptides / Q000032:analysis*; D006801:Humans; D007071:Immunoglobulin A, Secretory; D009682:Magnetic Resonance Spectroscopy; D000432:Methanol; D008745:Methylation; D008895:Milk, Human / Q000276:immunology*
chemical_list: D002241:Carbohydrates; D006020:Glycopeptides; D007071:Immunoglobulin A, Secretory; D000432:Methanol