The structure of carbohydrate unit B of porcine thyroglobulin.
The oligosaccharide fraction was obtained from porcine thyroglobulin by hydrazinolysis. Four fractions of unit B-type oligosaccharides were purified by successive chromatographies on columns of DEAE-cellulose and concanavalin A-Sepharose, and their structures were investigated by the combination of endo- and exo-glycosidase digestions, methylation analysis and Smith degradation. From the results of these studies, the structures of the unit B oligosaccharides were proposed to be as follows: see formula in text. Thus the glycoprotein was found to have triantennary and biantennary complex-type oligosaccharides as acidic sugar chains. Concerning the triantennary oligosaccharides, the following structural features were shown: (1) the sialic acid residues were not localized on certain specific branches but distributed on all three branches; (2) however, alpha (2 leads to 3)-linked sialic acid residues were exclusively located on the terminal of the branch arising from C-4 of the branching alpha-mannose residue, whereas alpha (2 leads to 6)-linked sialic acid residues occupied terminals of the other branches; (3) the outer branching alpha-mannose residue was attached to C-3 or C-6 of an inner branching beta-linked mannose residue, and both types were observed to exist.
D000818:Animals; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000032:analysis*; D002846:Chromatography, Affinity; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D006026:Glycoside Hydrolases; D008745:Methylation; D009844:Oligosaccharides / Q000032:analysis; D012794:Sialic Acids / Q000032:analysis; D013552:Swine; D013954:Thyroglobulin
D002241:Carbohydrates; D009844:Oligosaccharides; D012794:Sialic Acids; D013954:Thyroglobulin; D006026:Glycoside Hydrolases