Preliminary investigation into the purification, NMR analysis, and molecular modelling of chondroitin sulphate epitopes.

Electrophoretic methods are outlined for the rapid purification and analysis of chondroitin sulphate oligosaccharides on a milligram scale. Isomeric impurities however, exist within specific sized oligosaccharides. Detailed 1H and 13C NMR data for the chondroitin sulphate disaccharides delta 4HexA(1-3)GalNAc6SO3- and delta 4HexA(1-3)GalNAc4SO3- (prepared from shark chondroitin sulphate) are reported. Two-dimensional NMR methods have been employed in the assignment of spectra. Preliminary models of these disaccharides are proposed from molecular mechanics conformational searching and molecular dynamics procedures. This study provides 1H and 13C NMR reference data which will be useful in the investigation of larger chondroitin sulphate oligosaccharides, such as those prepared by the electrophoretic methods mentioned above.

Structural characterization of neutral oligosaccharides with blood-group A and H activity isolated from bovine submaxillary mucin.

In this study we investigated the structures of 11 neutral oligosaccharides released from bovine submaxillary mucin by alkaline borohydride treatment and isolated by h.p.l.c. One hexa-, one penta-, three tetra-, four tri- and two di-saccharides containing core types 1, 2, 3 or 4 were obtained. We report their structures, determined by a combination of one- and two-dimensional 1H n.m.r. spectroscopy at 270 MHz and methylation analysis involving g.l.c.-m.s., along with their approximate molar ratios. Only three of these oligosaccharides have previously been reported in this source. Of the new oligosaccharides, one contains the blood-group-A antigenic determinant, two contain the blood-group-H type 2 determinant, while another contains the blood-group-H type 3 determinant. The oligosaccharide GlcNAc beta (1----6)[GlcNAc beta (1----3)]GalNAcol, although previously found as a core structure, has been isolated here as a novel trisaccharide.

Structure determination of five sialylated trisaccharides with core types 1, 3 or 5 isolated from bovine submaxillary mucin.

In this study we have investigated the structures of five sialylated trisaccharides released from bovine submaxillary mucin by alkaline borohydride treatment and isolated by high-performance liquid chromatography. Three of the trisaccharides contained NeuAc while two contained NeuGc. One oligosaccharide contained core-type 1, two contained core-type 3 and two contained core-type 5. The structures, determined by a combination of one- and two-dimensional 1H-NMR spectroscopy at 270 MHz and methylation analysis involving gas-liquid chromatography/mass spectrometry, were as follows: A4b, GalNAc alpha(1----3) [NeuAc alpha(2----6)]GalNAcol; A4c, GlcNAc beta(1----3)[NeuAc alpha(2----6)]GalNAcol; A4d, Gal beta(1----3)[NeuAc alpha(2----6)]GalNAcol; A4e, GalNAc alpha(1----3)-[NeuGc alpha(2----6)]GalNAcol; A4f, GlcNAc beta(1----3)[NeuGc alpha (2----6)]GalNAcol. The oligosaccharides occurred in the approximate molar ratios 1.0:12.0:0.3:0.2:2.0. This is the first report of oligosaccharides containing core-type 5 and of the occurrence of oligosaccharides A4b, A4e, and A4f in bovine submaxillary mucin. 1H-NMR data for structure A4e, which is a novel structure, are presented for the first time.

Determination of the structure of a novel acidic oligosaccharide with blood-group activity isolated from bovine submaxillary-gland mucin.

In this study we investigated the structure of an acidic fucose-containing pentasaccharide released from bovine submaxillary-gland mucin by alkaline-borohydride treatment. The structure, determined by a combination of one-dimensional and two-dimensional 1H-n.m.r. spectroscopy at 270 MHz and methylation analysis involving g.l.c.-m.s., was as follows: Fuc alpha(1----2)Gal beta(1----4)GlcNAc beta(1----3)[NeuAc alpha(2----6)]GalNAcol This pentasaccharide is a novel structure and is the first report of a blood-group-H type 2 determinant on a submaxillary-gland mucin.