title: Structures of the major oligosaccharides from a human rectal adenocarcinoma glycoprotein.
abstract: Four oligosaccharides in the reduced form were isolated from RMG (a mucin-type glycoprotein from a human rectal adenocarcinoma). They were 1) Sia alpha s2 leads to 6GalNAc-ol; 2) Sia alpha 2 leads to 6(Gal beta 1 leads to 3)GalNAc-ol; 3) Sia alpha 2 leads to 6(GlcNAc beta 1 leads to 3)GalNAc-ol; and 4) Sia alpha 2 leads to 6(GalNAc alpha 1 leads to 3)GalNAc-ol. The amounts of oligosaccharides 1, 2, 3, and 4 corresponded to 27, 5, 11, and 8% of the total N-acetylgalactosaminitol produced on alkaline borohydride treatment of RMG. To determine the structures of oligosaccharides 2, 3, and 4, a mixture of the three was subjected to methylation analysis which revealed that the N-acetylgalactosaminitol was substituted at both C-3 and C-6 and other sugars at the nonreducing ends. Desialized oligosaccharides were prepared, and the structures were deduced by analysis of the permethylated sugars on gas-liquid chromatography/mass spectrometry. Anomeric configurations were determined by exoglycosidase digestions except for galactose which was analyzed by chromium trioxide oxidation.
mesh_terms: D000230:Adenocarcinoma / Q000032:analysis*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002849:Chromatography, Gas; D002854:Chromatography, Paper; D006023:Glycoproteins / Q000302:isolation & purification*; D006801:Humans; D013058:Mass Spectrometry; D008745:Methylation; D009363:Neoplasm Proteins / Q000302:isolation & purification*; D009844:Oligosaccharides / Q000032:analysis*; D012004:Rectal Neoplasms / Q000032:analysis*
chemical_list: D006023:Glycoproteins; D009363:Neoplasm Proteins; D009844:Oligosaccharides