Separation of acidic oligosaccharides by liquid chromatography: Application to analysis of sugar chains of glycoproteins

Abstract

An ion-exchange, chromatographic system was developed to separate acidic oligosaccharides. Application of this system for the analysis of sialylated carbohydrate chains of glycoproteins was examined, and it was found that this system affords high resolution of acidic oligosaccharide isomers. ( 1) 3′- O-Neuraminyllactose, 6′- O-neuraminyllactose, and N-acetyl-6′- O-neuraminyllactosamine could be separated from bovine colostrum. ( 2) Subjection, to this system, of the oligosaccharide fraction released from bovine submaxillary mucin by treatment with alkaline borohydride resulted in good separation of the trisaccharide-alditol GlcNAc-(1→3)-[NeuAc-(2→6)]-GalNAcol and the disaccharide-alditol NeuAc- or NeuGc-(2→6)-GalNAcol. ( 3) When the serine- or threonine-linked oligosaccharide fraction obtained from human glycophorin A was subjected to this system, two monosialosylated, trisaccharide-alditol isomers, namely, NeuAc-(2→3)-Gal(1→3)-GalNAcol and Gal-(2→3)-[NeuAc-(2→6)]-GalNAcol, could be separated from each other. ( 4) The separation of so-called triantennary and biantennary, complex type of sugar chains of porcine thyroglobulin was achieved with this system.