Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “OLIGOSACCHARIDES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,261 records · Page 70Linked to original sources
PubMed1988

Modulation of oligosaccharide processing in an exocrine secretory glycoprotein of rat parotid cells by beta-adrenoreceptor activation.

Such stimulation of rat parotid acinar cells in vitro modulated the rate of processing of N-linked oligosaccharides in a high-molecular weight (220 kdalton) secretory glycoprotein. Conversion of polymannose-type oligosaccharides to complex-type oligosaccharides was evaluated by sensitivity to endoglucosaminidase H and alpha-mannosidase, and with a specific inhibitor of glucosidases I/II. Oligosaccharide maturation in the 220 kdalton glycoprotein required one-third to half less time in cells exposed to the beta-adrenergic agonist isoproterenol than in controls.

1-Deoxynojirimycin↗
PubMed1975

Specificity studies on alpha-mannosidases using oligosaccharides from mannosidosis urine as substrates.

Oligosaccharides containing terminal non-reducing alpha(1 leads to 2)-, alpha(1 leads to 3)-, and alpha(1 leads to 6)-linked mannose residues, isolated from human and bovine mannosidosis urines were used as substrates to test the specificities of acidic alpha-mannosidases isolated from human and bovine liver. The enzymes released all the alpha-linked mannose residues from each oligosaccharide and were most effective on the smallest substrate. Enzyme A in each case was less active on the oligosaccharides than alpha-mannosidase B2, even though the apparent Km value for the substrates was the same with each enzyme. The human acidic alpha-mannosidases were also found to be more active on substrates isolated from human rather than bovine mannosidosis urine. Human alpha-mannosidase C, which has a neutral pH optimum when assayed with a synthetic substrate, did not hydrolyse any of the oligosaccharides at neutral pH, but was found to be active at an acidic pH.

Animals↗
PubMed1981

Either high-mannose-type or hybrid-type oligosaccharide is linked to the same asparagine residue in ovalbumin.

After pepsin digestion, all of the carbohydrates in ovalbumin were recovered in two glycopeptides, Glu-Glu-Lys-Tyr-Asn(CHO)-Leu-Thr-Ser-Val and Glu-Gln-Lys-Tyr-Asn(CHO)-Leu-Thr-Ser-Val. Almond glycopeptidase released quantitatively oligosaccharides from the glycopeptides. The products from both glycopeptides contained both the high-mannose-type oligosaccharides and the hybrid-type oligosaccharides in the same ratio. Thus, either the high-mannose-type or the hybrid-type oligosaccharide is attached to the unique asparagine residue in the ovalbumin molecule.

Amidohydrolases↗
PubMed1987

Multiple oligosaccharide chains in the voltage-sensitive Na channel from electrophorus electricus: evidence for alpha-2,8-linked polysialic acid.

Carbohydrate substituents on the large peptide of the voltage-sensitive Na channel from Electrophorus electricus electroplax have been partially characterized by their sensitivity to endoglycosidases H and F, peptide:N-glycosidase F, Endo-N-acetylneuraminidase, and to neuraminidase. The results suggest the presence of at least two classes of oligosaccharides: neutral, high mannose or hybrid oligosaccharides, and acidic, complex oligosaccharides with a core-structure terminating in an unbranched homopolymer of sialosyl units in alpha-2,8 linkages (much greater than 5 tandem sialic acids). Large decreases in apparent Mr produced by sialidase treatments suggest an extended carbohydrate structure that could inhibit protein-protein interaction. Polysialic acid was formerly proposed to be a unique constituent of neural cell adhesion molecules (N-CAMs) in vertebrates. However, ratios of sialic acid to galactose reported for mammalian brain and muscle Na channels suggest they may also carry this oligosaccharide.

Animals↗
PubMed1990

A phospho-oligosaccharide can reproduce the stimulatory effect of insulin on glycolytic flux in human fibroblasts.

It has been recently demonstrated that insulin promotes the hydrolysis of a glycosyl-phosphatidylinositol, stimulating the release of a phospho-oligosaccharide which displays several insulin-like effects. In the present study we have investigated whether the compound is able to mimic insulin action on glucose metabolism in human fibroblasts. Similarly to the hormone, the phospho-oligosaccharide elicited a dose dependent increase in lactate output and fructose 2,6-bisphosphate content. The effect of the compound was time dependent with a progressive increase starting from 2 hours of incubation. 1 microM phospho-oligosaccharide had half maximal effect on both parameters, increasing glycolytic flux by approximately 30% and fructose 2,6-bisphosphate content by 70%. Therefore the phospho-oligosaccharide appears to be able to strictly reproduce insulin action on glucose metabolism in human fibroblasts.

Cells, Cultured↗
PubMed1991

1H-NMR spectroscopy of manno-oligosaccharides of the beta-1,2-linked series released from the phosphopeptidomannan of Candida albicans VW-32 (serotype A).

Manno-oligosaccharides (DP 2 to greater than 15) were released by mild acid hydrolysis from the phosphopeptidomannan of a Candida albicans strain of A serotype (VW-32). Manno-oligosaccharides ranging from biose to heptaose were obtained in appreciable amount. Structural investigation of these oligosaccharides showed them to be of the beta-1,2-linked series. The occurrence of such compounds has already been reported in other strains of Candida albicans. We here report the assignment of the structural reporter groups of each of them, and general rules applicable for the 1H-NMR spectrum analysis of linear manno-oligosaccharide of general structure: Man(beta 1-2) [Man(beta 1-2)]nMan

Candida albicans↗
PubMed1992

Characterization of the oligosaccharide side chains on kainate binding proteins and AMPA receptors.

The amino acid sequences of the kainate binding proteins (KBPs) from frog and chicken brain are homologous with the carboxy terminal half of the rat brain AMPA receptors. In this study, we have characterized the oligosaccharide side chains present on the KBPs from chicken and frog brain, and the AMPA receptors (GluR1, GluR2, and GluR3) from rat brain. Deglycosylation of the asparagine-linked carbohydrates present on the chicken, frog, and rat receptor subunits with N-glycanase, resulted in decreases in the relative molecular weights (M(r)) of 3.4, 3.4, and 5.1 kDa respectively. Thus the percent of asparagine linked carbohydrate (based on M(r) values derived from SDS polyacrylamide gels) of the 49 kDa chicken, the 48 kDa frog, and the 107 kDa receptor rat subunits is 6.9, 7.1, and 4.8 percent respectively. No shifts in the M(r) were detected after treatment with neuraminidase indicating that sialic acid does not appear to be a major component of these receptors. Lectin binding studies demonstrated that both asparagine-linked and serine/threonine-linked oligosaccharides were present in the chicken, frog, and rat proteins. The data indicate that at least one of the asparagine linked oligosaccharide side chains appear to be of the complex or non-bisected hybrid type in all three species. The similarities in the glycosyl moieties of the chicken and frog kainate KBPs and the rat brain AMPA receptors suggests that the homology in the amino acid sequences between these proteins may extend to homology in their oligosaccharide sides chains as well.

Amidohydrolases↗
PubMed1982

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

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 to 3)-[NeuAc-(2 to 6)]-GalNAcol and the disaccharide-alditol NeuAc- or NeuGc-(2 to 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 to 3)-Gal(1 to 3)-GalNAcol and Gal-(2 to 3)-[NeuAc-(2 to 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.

Animals↗
PubMed1983

The structure of the repeating oligosaccharide unit of the pneumococcal capsular polysaccharide type 18C.

The structure of the repeating oligosaccharide of the pneumococcal capsular polysaccharide type 18C has been investigated. The repeating oligosaccharide, isolated from an aqueous hydrofluoric acid hydrolyzate of the polysaccharide, was shown, by fast atom bombardment-mass spectrometry, to have a molecular weight of 928, and to contain an O-acetyl group and a glycerol residue. Information about the sequence in the per-O-methylated oligosaccharide was derived from electron-impact mass spectrometry. Supporting data were obtained from methylation analysis, periodate and chromium trioxide oxidations, and enzymic and acid hydrolyses of the oligosaccharide. These studies indicated that the polysaccharide consists of the following pentasaccharide repeating unit. (formula see text)

Oligosaccharides↗
PubMed1983

31P- and 13C-n.m.r.-spectral and chemical characterization of the end-group and repeating-unit components of oligosaccharides derived by acid hydrolysis of Haemophilus influenzae type b capsular polysaccharide.

Haemophilus influenzae type b capsular polysaccharide [repeating unit, leads to 3)-beta-D-Ribf-(1 leads to 1)-D-Ribol-5-(PO2H leads to] was partially hydrolyzed with HCl to give oligosaccharides that were isolated by size-exclusion chromatography, and then characterized by 31P- and 13C-n.m.r.-spectral and chemical methods, in order to determine the end-group composition and, hence, the number-average chain-length (L). The ratio (approximately 17:8) of monophosphate end-groups to D-ribofuranose end-groups revealed the relative rates of hydrolysis of the phosphoric diester linkage and the glycosidic linkage in the repeating-unit structure. Cleavage of the phosphoric diester linkage was approximately 92% regioselective, as indicated by the approximately 12:1 ratio of D-ribofuranose monophosphate end-groups to D-ribitol monophosphate end-groups. The n.m.r. spectra of the oligosaccharide repeating-unit provided evidence for partial stereomutation (approximately 3-8%) that involved rearrangement of the D-ribofuranose phosphoric diester linkage and anomerization at C-1 of D-ribofuranose. Variously sized oligosaccharides (L = 4, 7, and 12), that had D-ribofuranose end-groups reacted with bovine serum albumin that had an average of approximately 9 adipyl hydrazide functionalities, to give, within experimental error, quantitative yields of the corresponding hydrazone-linked, oligosaccharide-protein conjugates.

Carbohydrate Conformation↗
PubMed1984

Isolation of sulfited oligosaccharides from glycoproteins treated with alkaline sulfite.

The oligosaccharide products resulting from treatment of mucin-type glycoproteins with alkali in the presence of the sulfite anion have been investigated. Treatment of fetuin and of tryptic glycopeptides from the human erythrocyte with this reagent resulted in the release of sulfited oligosaccharides identified as N-acetylsulfohexosamine (HexNAcSO3), alpha-NeuAc-(2----6)-HexNAcSO3, and alpha-NeuAc-(2----3)-Gal-(1----3 or 4)-[GlcNAc-(1----6)]-HexNAcSO3. In addition, 2.7 moles of sialic acid were released per mole of alpha-NeuAc-(2----6)-HexNAcSO3 from fetuin. The sulfohexosamine moiety is formed via unsaturated intermediates from a 3-O-substituted 2-acetamido-2-deoxy-D-galactosyl residue at the carbohydrate-peptide linkage site when this residue is not substituted at O-4 by another sugar residue. A reaction mechanism accounting for the release of the sulfited oligosaccharides from a 3-O- and 6-O-substituted hexosamine is proposed in which the oligosaccharide branch attached to O-6 is obtained as a specific fragment terminating in sulfohexosamine.

Animals↗
PubMed1988

The determination of the structure of blood group oligosaccharides from fully assigned 1H-n.m.r. spectra for solutions in non-aqueous solvents.

The fully assigned 1H-n.m.r. spectra of a blood group A tetrasaccharide and of a blood group H hexasaccharide in dimethyl sulfoxide and in pyridine by use of two-dimensional COSY and homonuclear Hartmann-Hann coherence transfer methods are reported. The 1H-n.m.r. spectra of both of these compounds in deuterium oxide had been previously assigned. Since the relative proton chemical shifts in the three solvents are quite different, resonances which overlap or are strongly coupled for one solvent may be well resolved for another, thus providing an extension of the method of complete proton assignments for determination of the structure of complex oligosaccharides. Although the rotational correlation times (tau c) of these oligosaccharides are similar to the reciprocal of the spectrometer frequency, either negative or positive n.O.e. values were measurable for both oligosaccharides in all three solvents in one-dimensional difference spectroscopy by taking advantage of the dependence of tau c on the solvent viscosity and, thus, on sample temperature. Whereas n.O.e. depend strongly on temperature and solvent viscosity, the ratios of the effects between protons on the same pyranoside ring and those on different rings were observed to be similar, suggesting that the oligosaccharide conformations are not strongly dependent on solvent or temperature.

ABO Blood-Group System↗
PubMed1988

Isolation and partial purification of lipid-linked oligosaccharides from calf pancreas.

Lipid-linked oligosaccharides containing at least five mannose residues (0.7 nmol/g of tissue) were isolated from calf pancreas by chloroform-methanol-water extraction and purification on DEAE-cellulose and Sephadex LH-20, and affinity chromatography on concanavalin A-Sepharose in the presence of nonionic detergent. The addition, prior to the chromatographic steps, of 14C-labeled lipid-linked oligosaccharides (synthesized in vitro by calf pancreas microsomes in the presence of GDP-D-[14C]mannose and UDP-D-[14C]glucose, respectively) as internal standards, indicated a final yield ranging from 38 to 50%. Analysis of the oligosaccharide residues by liquid chromatography of the lipid-free preparation, monitored by u.v. absorbance and radioactivity measurement of the tritiated compounds, indicated a heterogeneous mixture of oligosaccharides. Its components, ranging from Man5(GlcNAc)2 to Glc3Man9(GlcNAc)2, cochromatographed with the 14C-labeled derivatives from in vitro synthesis. Calf pancreas contains lipid intermediates bearing at least six mannose residues, such as Man9(GlcNAc)2-P-P-lipid, in almost equal or even higher amounts than Glc3Man9(GlcNAc)2-P-P-dolichol.

Animals↗
PubMed1990

Structural analysis of xyloglucan oligosaccharides by 1H-n.m.r. spectroscopy and fast-atom-bombardment mass spectrometry.

A method to determine rapidly the identities and proportions of the oligosaccharide repeating-units in plant cell-wall xyloglucans by 1D 1H-n.m.r. spectroscopy was developed. Six of the most commonly found xyloglucan oligosaccharide subunits (including three subunits that had not been fully characterized previously) were prepared by endo-(1----4)-beta-D-glucanase digestion of xyloglucans from various plant species. The oligosaccharides were reduced to the corresponding oligoglycosyl-alditols, purified, and characterized by glycosyl composition and linkage analysis, 1H-n.m.r. spectroscopy, and f.a.b.-mass spectrometry. Correlations between the 1H-n.m.r. spectra and the structures of the oligoglycosyl-alditols can be used to identify oligoglycosyl-alditols derived from xyloglucans of unknown structure. The identities and relative amounts of the oligosaccharide subunits of xyloglucans isolated from tamarind seed and rapeseed hulls were determined on this basis.

Carbohydrate Conformation↗
PubMed1991

High-performance reversed-phase chromatographic mapping of 2-pyridylamino derivatives of xyloglucan oligosaccharides.

Xyloglucan oligosaccharides from cotton cell walls and tamarind seeds were derivatized with 2-aminopyridine and subsequently separated by reversed-phase chromatography (r.p.c.) using an octadecylsilyl silica stationary phase and aqueous-organic eluents with 0.01% (v/v) trifluoroacetic acid. The chromatographic behavior of the 2-pyridylamino derivatives of xyloglucan oligosaccharides was examined under a wide range of elution conditions, including gradient steepness and shape, initial acetonitrile concentration in the eluent, and pore size of the r.p.c. packings. Relatively steep acetonitrile gradients resulted in poor resolution of the different xyloglucan fragments, which is believed to be the result of acetonitrile-induced conformational changes. Under these circumstances the elution order of the derivatized xyloglucan oligosaccharides was such that the smaller fragments eluted from the column before the larger ones. R.p.c. packing with a 70-A pore size necessitated relatively high acetonitrile concentration in the eluent when compared with 300-A stationary phase. The r.p.c. mapping of 2-pyridylamino derivatives of xyloglucan oligosaccharides was best achieved when both a wide-pore octadecyl-silyl silica stationary phase and a shallow gradient with consecutive linear segments of increasing acetonitrile concentration in the eluent were employed. This combination yielded rapid r.p.c. maps of the xyloglucan fragments from different sources with high separation efficiencies and concomitantly high resolution. The effects of the nature of the sugar residues in the xyloglucan oligomers and their degree of branching on r.p.c. retention and selectivity are also highlighted.

Aminopyridines↗
PubMed1992

One- and two-dimensional 13C-n.m.r. characterization of two series of oligosaccharides derived from porcine intestinal mucosal heparin by degradation with heparinase.

Two tetrasaccharides, two hexasaccharides, and a disaccharide have been purified from heparinase digests of porcine intestinal mucosal heparin in sufficient quantities to permit 13C-n.m.r. characterization of the species. The two tetrasaccharides are the sulfated iduronic acid-containing 4en-HexpA2SO3-(1----4)-alpha-D-GlcpNSO3;6SO3-(1- ---4)-alpha-L- IdopA2SO3-(1----4)-D-GlcpNSO3;6SO3 and the non-sulfated glucuronic acid-containing 4en-HexpA2SO3-(1----4)-alpha-D-GlcpNSO3;6SO3-(1- ---4)-beta-D-GlcpA-(1----4)-D- GlcpNSO3;6SO3. The two hexasaccharides are related to the two tetrasaccharides by the insertion of alpha-linked L-IdopA2SO3-(1----4)-D-GlcpNSO3;6SO3 after the non-reducing end sulfated glucosamine residue. The disaccharide is 4en-HexpA2SO3-(1----4)-alpha-D-GlcpNSO3;6SO3. The disaccharide, together with each of the iduronate-containing oligosaccharides, form one series of related di-, tetra-, and hexa-saccharides, while the disaccharide together with the glucuronate-containing oligosaccharides form a second series. Using inverse detection as a means of increasing sensitivity, two-dimensional n.m.r. 13C-1H heterocorrelation spectra have been obtained for all five oligosaccharides. The use of two-dimensional heterocorrelation n.m.r. spectroscopy offers a much less ambiguous means of making 13C resonance assignments than do traditional one-dimensional methods, while the use of inverse detection gives both greater sensitivity than direct detection, as well as values for the one-bond 13C-1H coupling constants. From a knowledge of the assignments of resonances in the 1H spectra of these species, it has been possible to assign almost all of the 13C resonances of these five oligosaccharides. Some corrections to previously published assignments for the tetrasaccharides have been made. In addition, one-bond 13C-1H coupling constant data have been obtained for all of the anomeric protons.

Animals↗
PubMed1995

Utility of non-covalent complexes in the matrix-assisted laser desorption ionization mass spectrometry of heparin-derived oligosaccharides.

Molecular weights of heparin-derived oligosaccharides ranging from disaccharides to hexadecasaccharides have been determined by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. While these compounds ionize poorly or not at all when used as such, a strong signal can be obtained of their ionic complexes formed with a basic peptide or protein. The molecular weight of the sulfated oligosaccharide is determined by subtracting the mass of the basic component from that of the complex. Optimization of the experimental conditions resulted in sub-picomole sensitivity, in the elimination of sulfate loss and of the interference from attachment of inorganic cations. Synthetic peptides (Arg-Gly)10 and (Arg-Gly)15 were specifically designed as complexing agents for synthetic and natural heparin fragments up to decasaccharides. Accurate molecular weight determination on chemically homogeneous oligosaccharides (+/- 0.05%) unambiguously identified the number of saccharide units, and the number of O,N-sulfate and N-acetyl groups. For oligosaccharides larger than decasaccharides, a small basic protein, angiogenin (M(r) = 14,120), was used to form the complex (an inhomogeneous hexadecasaccharide fraction was the largest available for this study). For inhomogeneous samples larger than decasaccharides, the mass accuracy is lower (+/- 0.2-0.3%) but still suffices to determine the number of saccharide units present and to estimate the number of sulfate groups, except it is no longer possible to differentiate one sulfate from two N-acetyl groups (delta = 4 Da). However, taking into account known regularities of sulfation and acetylation, the specificity of heparin lyases and chemical degradation steps, the method promises to contribute significantly to the determination of the primary structure of heparin and other sulfated glycosaminoglycans.

Amino Acid Sequence↗
PubMed1994

Synthesis of sulfated alkyl malto- and laminara-oligosaccharides with potent inhibitory effects on AIDS virus infection.

A series of sulfated alkyl oligosaccharides, including a sulfate dodecyl laminarapentaoside and a sulfated octadecyl maltohexaoside with potent anti-human immunodeficiency virus (HIV) activity, has been synthesized. An alkyl oligosaccharide in which a long alkyl group is bonded to the reducing end of the oligosaccharide was first synthesized in high yield. Peracetylated oligosaccharides reacted with such aliphatic alcohols as 1-decyl and 1-dodecyl alcohols with Lewis acids as catalysts. As in the glycosylation of the alpha and beta peracetylated glycosides, the beta anomer reacted exclusively, the acetylation was carried out with a sodium acetate-acetic anhydride at high temperatures to maximize the proportion of the beta anomer.

Acetylation↗