The isolation and the structure of new glycopeptide from blood group substances

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.

The use of gas chromatography and gas chromatography-mass spectrometry for the characterization of permethylated oligosaccharides with molecular mass up to 2300

Gas chromatography and gas chromatography-mass spectrometry were adapted for the analysis of large permethylated oligosaccharides of different types. Permethylated isomaltooligosaccharides with up to 11 sugar residues and a mass of 2291 Da and two branched blood group H-type decasaccharides derived from the corresponding glycosphingolipids with masses of 2150 Da were successfully analyzed. The capillary columns used have extremely good resolution exemplified by the separation of the two decasaccharides which only differed by one internal linkage position and by the separation of four isomeric tetrasaccharides. The combined information of retention times and mass spectra gave detailed information of 22 neutral oligosaccharides from porcine intestinal mucin and the approach thus allow quick screening of O-linked-type glycans. The procedure for permethylation of oligosaccharides using solid NaOH has been investigated and adapted for structures having a glucose alditol as in reduced oligosaccharides derived from milk and glycosphingolipids.

UDP-GalNAc:GalNAc-mucin alpha-N-acetylgalactosamine transferase activity in human intestinal cancerous tissues

GalNAc transferase activities of 6 human intestinal cancerous tissues were examined using bovine submaxillary gland mucin and its desialylated derivative, asialomucin, as acceptors. A Triton X-100 extract of these tissues was used an an enzyme source. All the tissues examined had GalNAc transferase that catalyzes the transfer of GalNAc from UDP-GalNAc to serine or threonine residues of the polypeptide chain. One of 6 specimens showed in addition UDP-GalNAc:GalNAc-mucin alpha-GalNAc transferase activity, synthesizing a disaccharide unit, GalNAc alpha----GalNAc, when asialomucin was used as an acceptor. This carbohydrate structure was deduced on the basis of results of gel filtration, exoglycosidase digestion, and high-voltage paper electrophoresis.

Structural analysis of the O-glycosidically linked core-region oligosaccharides of human meconium glycoproteins which express oncofoetal antigens

Glycoproteins were extracted from meconium samples of group O neonates of secretor type by pronase digestion followed by precipitation in 67% aqueous ethanol and separated into Ii antigen enriched and depleted fractions by affinity chromatography. The latter fraction strongly expressed the oncofoetal antigens recognised by natural antibodies in mouse sera and the hybridoma antibody FC 10.2, and this activity was enhanced after mild acid hydrolysis to remove sialic acid and fucose residues. Oligosaccharides were released from the mild-acid-treated fraction by base-borohydride degradation and purified by gel permeation chromatography on Bio-Gel P4 and high performance liquid chromatography on octadecylsilyl and aminopropylsilyl columns. The major oligosaccharides were characterised by fast atom bombardment and electron impact mass spectrometry, combined gas-liquid chromatography/mass spectrometry and 500-MHz proton NMR spectroscopy. Their structures, in order of abundance, were: (Formula: see text).

A versatile immunoadsorbent capable of binding lectins of various specificities and its use for the separation of cell populations

A procedure for cell fractionation using lectin-affinity chromatography is described. It consists of a single affinity adsorbent, hog gastric mucin blood group A+H substance covalently coupled to Sephadex or Sepharose, to which lectins of various specificities can bind. The complex formed, lectin in equilibrium hog A+H substance-Sephadex, then serves as an affinity probe for isolating and fractionating cells. The lectins from Ulex europaeus, Lotus tetragonolobus, Helix pomatia, Dolichos biflorus, and Phaseolus lunatus were used with the same blood group substance as adsorbent. The affinity columns retained erythrocytes with blood group specificity for the adsorbed lectin and thus fractionate cells in mixtures. Cells as well as lectins are eluted by specific sugar inhibitors. Mixtures of two kinds of cells can be separated when the proportion of the adsorbed cells is not too low.

The structure of carbohydrate chains of blood-group substance. Isolation and elucidation of the structure of higher oligosaccharides from blood-group substance H

Twenty individual higher reduced oligosaccharides, having from seven to eleven monosaccharide units, were isolated after sodium borohydride degradation of blood-group substance H from pig stomach linings. Anion-exchange high-pressure liquid chromatography appears to be a very convenient and effective method for this kind of higher oligosaccharide mixtures separation. The oligosaccharide structures were determined by means of periodate oxidation, methylation analysis, partial acid and enzymic hydrolysis. It has been found that all the oligosaccharides investigated can be divided into four series. The oligosaccharides belonging to each series have the common oligosaccharide fragment to which terminal L-fucose and/or N-acetyl-D-glucosamine residues are attached. Comparison of all the oligosaccharide structures, including tri, penta and hexasaccharides described earlier, shows that the lower oligosaccharides represent the structural element of the higher oligosaccharides.