title: Structure of the complex oligosaccharides of fetuin.
abstract: The complete structure of the complex oligosaccharides of fetuin has been established. The three fractions of complex oligosaccharide which were isolated by ion exchange chromatography following pronase digestion (F-I, F-II, and F-III) had identical molar ratios of sialic acid (Sia), galactose, mannose, and N-acetylglucosamine of 3:3:3:5. A combination of methylation analyses, Smith periodate degradations, and endoglycosidase and exoglycosidase digestions were utilized to establish the structure which is proposed to be: (see article of journal). Features of this structure not previously established include the presence of 2 residues of alpha2,3- and 1 residue of alpha2,6-linked sialic acid and their location relative to the mannose branch points. Also unusual is the presence of an alpha-linked branch mannose with substituents at positions 2 and 4 which is in turn linked to position 6 of the beta-linked, branch mannose. These features result in unexpected resistance to specific exoglycosidases.
mesh_terms: D002241:Carbohydrates / Q000032:analysis; D006020:Glycopeptides / Q000032:analysis; D008745:Methylation; D008968:Molecular Conformation; D008970:Molecular Weight; D009844:Oligosaccharides; D000509:alpha-Fetoproteins
chemical_list: D002241:Carbohydrates; D006020:Glycopeptides; D009844:Oligosaccharides; D000509:alpha-Fetoproteins