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PubMed2002

Analysis of phosphate position in hexose monosaccharides using ion-molecule reactions and SORI-CID on an FT-ICR mass spectrometer.

Through the use of ion-molecule reactions and SORI-CID, the phosphate position in hexose phosphate monosaccharides has been determined in the negative ion mode. Trimethyl borate was used as a reagent gas and was found to react readily with the phosphorylated hexose monosaccharides. After reaction of the reagent gas with the hexose phosphate, ion activation of the precursor by SORI-CID yielded different MS/MS spectra. Different diagnostic ions were generated for the two isomers, thus enabling differentiation and linkage position determination of the phosphate moiety.

Fourier Analysis↗

PubMed1999

Differentiation of diastereomeric N-acetylhexosamine monosaccharides using ion trap tandem mass spectrometry.

A quadrupole ion trap mass spectrometer equipped with electrospray ionization was used to distinguish three diastereomeric monosaccharides, N-acetylglucosamine, N-acetylgalactosamine, and N-acetylmannosamine. The saccharides were derivatized to form the metal complex [CoIII(DAP)2HexNAc]Cl3 which, when collisionally activated, produced dramatically different product ion spectra. The product ion spectra generated for the three monosaccharide diastereomers were then used to confirm the stereochemistry of N-acetylhexosamines from a hydrolyzed oligosaccharide. Finally, the origin of each product ion was determined through isotopic labeling studies, and mechanisms were proposed which explain each resulting dissociation.

Hexosamines↗

PubMed2003

Determination of free proline and monosaccharides in wine samples by high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD).

A sensitive and selective analytical method for the simultaneous separation and quantitative determination of proline and free monosaccharides in wine samples by high-performance anion-exchange chromatography coupled with pulsed amperometric detection is described. Under optimized experimental conditions, a complete separation was obtained in less than 30 min, using an isocratic elution with 10 mM NaOH and 1 mM Ba(OAc)(2). No postcolumn addition of strong bases to the eluent for enhancing detection sensitivity was needed. Upon 25-fold sample dilution and purification to avoid interference of tannins, pigments, and phenolic compounds, the fingerprinting of common monosaccharides (i.e., arabinose, glucose, fructose, galactose, and xylose) and proline in wines, musts, and vinegars can be easily accomplished. The method allows high recovery and satisfies the necessary requirements for accuracy, repeatability, and sensitivity. Values obtained for proline content ranged from 470 to 1190 mg/L in "Aglianico" red wines (mean value, 870 +/- 192 mg/L, n = 21) and from 168 to 286 mg/L in white wines (mean value, 208 +/- 32 mg/L, n = 11). Lower levels were found in musts of red and white grapes, 550 and 87 mg/L, respectively. The lowest content of proline, ca. 10 mg/L, was found both in white and red vinegars.

Acetic Acid↗

PubMed2006

The true Johari-Goldstein beta-relaxation of monosaccharides.

Broadband isothermal dielectric relaxation measurements of anhydrous fructose, glucose, galactose, sorbose, and ribose were made at ambient pressure in their liquidus and glassy states. We found a new secondary relaxation in fructose and glucose that is slower than those seen before by others. This new secondary relaxation also appears in the dielectric spectra of galactose, sorbose, and ribose, and hence it is a general feature of the relaxation dynamics of the monosaccharides. Dielectric measurements at elevated pressure of fructose and ribose show that the new secondary relaxation shifts to lower frequencies with applied pressures, mimicking the behavior of the alpha-relaxation. In contrast, the faster secondary relaxation remains stationary on applying pressure. These results together with other inferences indicate that the slower secondary relaxation bears relations to the alpha-relaxation, and hence, it is the true Johari-Goldstein secondary relaxation of the monosaccharides.

Molecular Structure↗

PubMed2004

In situ studies of monosaccharide gelation using the small-angle X-ray scattering time-resolved method.

The process of gelation of one of the monosaccharides, alpha-galactose-based gelator, with benzene as a solvent, has been studied. Small-angle X-ray scattering (SAXS) synchrotron time-resolved measurements were performed throughout the gelation process. The obtained SAXS measurements were elaborated using such methods as the fractal analysis, Fourier transform to get distance distribution functions, and simulation of a cluster model. We obtained the picture of the mesostructure development from the sol state to the gel state. Our results indicate that the fractal-type aggregates exist in the sol and the process of gelation is accompanied by the structural transition. This transition causes the aggregates to become smaller and denser, and their shapes differ from those of the sol. The complex method of SAXS data treatment we established seems to be a useful tool also for further studies of monosaccharide gelation.

Algorithms↗

PubMed2001

New color chemosensors for monosaccharides based on azo dyes.

Sugar detection is important for many applications. New developments in sugar signaling would provide new technologies to monitor glucose and other sugars. Azo dye 1 presents a new way to build molecular color sensors for monosaccharides. The boronic acid group is used as chelator group for monosaccharides and linked directly in resonance with the aromatic dye. Dye 1 shows a color change, from orange to purple, in the presence of sugar at neutral pH. [structure: see text]

Azo Compounds↗

PubMed2000

Synthesis and reactivity of the monosaccharide esters of amino acids as models of teichoic acid fragment.

The increasing prevalence of sepsis from gram-positive bacterial pathogens necessitates further evaluation of the basic assumptions about the molecular pathogenesis of septic shock. Since diverse physiological functions of gram-positive bacteria are controlled by the degree of esterification of teichoic acids with D-alanine, we examined the reactivity of monosaccharide esters in which anomerically free or protected D-glucose is linked through its C-6 hydroxy group to either phenylalanyl or tyrosyl residues as models for teichoic acid fragment. We show that the attached sugar moiety induces activation of the amino acid residue. Due to the enhanced reactivity of the NH2 group in the monosaccharide esters studied, the formation of products generated by intramolecular and intermolecular glycation reactions is accelerated resulting in heterogeneous mixture of compounds. These findings suggest that, if similar adducts are formed by glycation of D-alanine in teichoic acid of gram-positive bacteria, they should be examined as potential bioactive ligands or chemical message for infection.

Amino Acids↗

PubMed2001

One of two tandem Arabidopsis genes homologous to monosaccharide transporters is senescence-associated.

A gene designated SFP1, which is similar to major facilitator superfamily monosaccharide transporters, is induced during leaf senescence. Genomic sequence analysis identified a second highly similar and closely linked gene, SFP2, suggesting that SFP1 and SFP2 may have arisen through a recent duplication event. However, RNA gel-blot analyses and histochemical localization of a reporter gene activity in transgenic plants show that SFP1 and SFP2 are differentially regulated and that only SFP1 is induced during leaf senescence. The increase in SFP1 gene expression during leaf senescence is paralleled by an accumulation of monosaccharides. Possible roles for SFP1 in sugar transport during leaf senescence are discussed.

Amino Acid Sequence↗

PubMed1965

The use of gas-liquid chromatography in the analysis of neutral monosaccharides in hydrolysates of gastric mucopolysaccharides.

1. Conditions are described for the separation and estimation of the neutral monosaccharides obtained on acidic hydrolysis of human gastric mucopolysaccharides. 2. The technique involves the formation of the trimethylsilyl derivatives of the sugars and the analysis of these by gas-liquid chromatography. 3. The monosaccharides estimated in gastric mucopolysaccharides by this technique were l-fucose, d-mannose, d-galactose and d-glucose. 4. The analytical values for glucose and fucose obtained by this method agreed well with values obtained by the glucose oxidase and thioglycollic acid methods respectively. 5. Evidence is presented which clearly indicates that gas-liquid chromatography is a faster, more sensitive and more convenient technique for the measurement of these compounds than any other in use at present.

Chromatography, Gas↗

PubMed1968

A new method for the quantitative determination of monosaccharides, amino sugars and N-acetylneuraminic acid and of 6-deoxyhexose (fucose) in the presence of other sugars.

1. Monosaccharides, amino sugars and N-acetylneuraminic acid were determined by using an original colorimetric assay procedure, based on the detection of formaldehyde released after periodate oxidation. A range of these compounds was investigated by this method and they were all found to obey Beer's law within the concentration range 0-0.6mumole/ml. 2. A simple method for the determination of 6-deoxyhexose concentration in the presence of other monosaccharides is also described. 3. The optimum pH for the release of formaldehyde from sugars by periodate oxidation was 7.0-7.5. 4. The methods described have considerable advantages over existing assay systems and their particlar value in automatic colorimetry, where the use of concentrated acids is undesirable, is discussed.

Amino Sugars↗

PubMed1992

Metabolic fates of U-14C-labelled monosaccharides and an enzyme-treated cell-wall substrate in the fowl.

A major benefit of supplementing non-ruminant feedstuffs with exogenous enzymes is presumed to be the degradation of plant cell-wall polysaccharides to metabolizable monosaccharide residues. In the present study, metabolic fates of (U-14C-labelled, 10 mM) glucose, galactose, mannose, xylose and arabinose were compared in the fowl, by measuring recoveries of 14C radioactivity in exhaled carbon dioxide excreta and body tissues after administration either by wing vein (iv) or into the crop (ic). A further comparison was made with a tube-fed, enzyme-treated, U-14C-labelled cell-wall substrate, Festuca arundinacea, and a final experiment tested possible competition for absorption between different cell-wall residues. Delays between iv and ic treatments in recovery of 14C in CO2, which were assumed to reflect intestinal absorption, indicated that xylose was absorbed more slowly than glucose and galactose, but faster than mannose and arabinose. Total recoveries of 14C in CO2 and excreta over the whole test period indicated that metabolizabilities were highest with glucose, galactose and mannose, and lowest with arabinose. After testing, 14C recovery in caecal contents was highest with ic arabinose, and recoveries in body tissues, with all sugar treatments, were in the order liver greater than breast and leg muscle greater than abdominal fat greater than plasma. Results with the Festuca substrate showed similar patterns of recovery in body tissues and confirmed an increase in metabolizability with addition of enzyme. The timing of the 14CO2 response with Festuca and a wet enzyme pretreatment was broadly similar to a 'predicted Festuca' response, based on the composition of the substrate and the measured responses with individual (ic) monosaccharides. There was no evidence of any competition for absorption or metabolism among cell-wall residues. It was concluded that glucose release from cellulose is potentially the most important product of cell-wall degradation to contribute to enzyme enhancement of metabolizable energy.

Animals↗

PubMed1991

Molecular modelling of protein-carbohydrate interactions. Docking of monosaccharides in the binding site of concanavalin A.

A general procedure is described for addressing the computer simulation of protein-carbohydrate interactions. First, a molecular mechanical force field capable of performing conformational analysis of oligosaccharides has been derived by the addition of new parameters to the Tripos force field; it is also compatible with the simulation of protein. Second, a docking procedure which allows for a systematic exploration of the orientations and positions of a ligand into a protein cavity has been designed. This so-called 'crankshaft' method uses rotations and variations about/of virtual bonds connecting, via dummy atoms, the ligand to the protein binding site. Third, calculation of the relative stability of protein ligand complexes is performed. This strategy has been applied to search for all favourable interactions occurring between a lectin [concanavalin A (ConA)] and methyl alpha-D-mannopyranoside or methyl alpha-D-glucopyranoside. For each monosaccharide, different stable orientations and positions within the binding site can be distinguished. Among them, one corresponds to very favourable interactions, not only in terms of hydrogen bonding, but also in terms of van der Waals interactions. It corresponds precisely to the binding mode of methyl alpha-D-mannopyranoside into ConA as revealed by the 2.9 A resolution of the crystalline complex (Derewenda et al., 1989). Some implications of the present modelling study with respect to the molecular basis of the specificity of the interaction of lectins with various monosaccharides are presented.

Binding Sites↗

PubMed1994

Monosaccharide and oligosaccharide analysis of isoelectric focusing-separated and blotted granulocyte colony-stimulating factor glycoforms using high-pH anion-exchange chromatography with pulsed amperometric detection.

In this study, a sensitive, straightforward technique is developed for the analysis of glycoprotein O-linked oligosaccharides. Specifically, O-linked oligosaccharides of granulocyte colony-stimulating factor (G-CSF) are analysed by separating charged glycoforms using isoelectric focusing, electroblotting to polyvinylidene difluoride, releasing monosaccharides and oligosaccharide alditols from the blotted glycoprotein bands, and producing chromatographs using high-pH anion-exchange chromatography with pulsed amperometric detection. Using this technique, the O-linked structures of G-CSF produced by recombinant Chinese hamster ovary (CHO) cells are deduced by comparison with monosaccharide and oligosaccharide standards. Lectin blotting and peptide sequencing support the identities of the presumed G-CSF glycoforms. The two major glycoforms determined using this methodology correspond to those determined previously for CHO-produced G-CSF using NMR. Additional glycoforms are also identified in this study, presumably resulting from the presence of N-glycolyneuraminic acid in place of N-acetylneuraminic acid. The utility of this analytical approach is then demonstrated in an analysis of the effect of the extracellular environment on the O-linked glycosylation of G-CSF by recombinant CHO cells. Increasing the level of ammonium ion in the culture medium is shown to reduce the percentage of G-CSF produced with sialic acid linked alpha (2,6) to N-acetylgalactosamine.

Amino Acid Sequence↗

PubMed1991

Anti-human immunodeficiency virus type 1 activity of sulfated monosaccharides: comparison with sulfated polysaccharides and other polyions.

Previously, the anti-human immunodeficiency virus type I (HIV-1) activities were reported of four sulfated polysaccharides: dextran sulfate, pentosane polysulfate, chondroitin sulfate, and heparin sulfate. In the present study, the anti-HIV-1 activities of several other sulfated polysaccharides, monosaccharides, neutral polysaccharides, and polypeptides were evaluated. Anti-HIV-1 activities of these various agents were measured by four different assays: (1) HIV-1-induced syncytia formation; (2) infectivity of cell-free HIV-1 after preincubation with the putative anti-HIV-1 agent; (3) protective ability of the agents for target CD4+ cells, and (4) anti-reverse transcriptase activity. In addition, potential toxicity of the putative anti-HIV-1 agents was measured by their effects on cellular proliferation, cytotoxic effects, and effects on coagulation processes. These data indicate that only sulfated polysaccharides and one sulfated monosaccharide, glucosamine 6-sulfate, have significant anti-HIV-1 activity. The therapeutic potentials of these agents are also discussed, with special reference to absorption of glucosamine 6-sulfate through the gastrointestinal tract.

Blood Coagulation↗

PubMed1984

The digestion of total and cell wall monosaccharides of alfalfa by sheep.

The effect of dietary starch on the digestibility of total and cell wall (CW) monosaccharides of alfalfa hay, was examined in sheep equipped with rumen and duodenal cannulas. The experiment consisted of two treatments. In one of them the sheep received 803 g dry matter (DM) of alfalfa hay (A), and in the second, 242 g DM alfalfa hay + 553 g of a purified starchy concentrate mixture (A + conct ). Rumen volume was not significantly different between treatments, but the mean retention time of markers in the rumen was shorter, and their rate of passage was faster in the A treatment than in the A + conct treatment. The overall digestibility of total CWs and CW constituents was not depressed in the A + conct treatment, the values for total CW being: 58.2 and 58.9% for the A and A + conct treatments, respectively. However, the digestion of CW monosaccharides in the rumen of the A + conct sheep was reduced despite the 100% longer retention time of particles in the rumen. The complimentary digestion of the potentially digestible CW monosacharides has been completed in the hindgut. The digestibility of CW glucose was higher (72%) than that of xylose (57%) in both treatments. CW glucuronic acid was the least digestible constituent (40%). Soluble uronic acids, representing the pectic material, were highly digestible (86.5% in A), but this was reduced to 80.3 in the A + conct treatment.

Animals↗

PubMed1976

Studies on a microchemical method for the determination of the degree of polymerization of neutral oligo- and polysaccharides. I. Quantitative separation of trace amounts of alditols from mixtures with a large excess of monosaccharides.

A method has been devised for the quantitative separation of trace amounts of alditols from mixtures with large amounts of monosaccharides, using a strongly basic ion-exchange resin. Ten kinds of common reducing monosaccharides used were strongly retained by a very basic anion-exchange resin in the hydroxyl form, whereas the corresponding alditols showed no significant affinity for the basic resin. Model studies showed excellent recoveries of alditol from known mixtures of alditol and the corresponding aldose at ratios in the range from 1 : 1X10(3) TO 1 : 1X10(4) (by weight). Application of this procedure to dextrans after reduction and hydrolysis resulted in quantitative separation of the terminal alditol.

Borohydrides↗

PubMedDate not supplied

Complex formation of p-boronophenylalanine with some monosaccharides.

To increase the solubility of p-boronophenylalanine (p-bpa) in neutral pH solution, the complex formation of p-bpa with some monosaccharides has been studied by 11B-NMR and UV spectroscopy. The complex formation constants (log K) obtained by the UV method in pH 7.4 solution are 2.43 (fructose), 2.19 (mannitol), 1.28 (galactose), 1.10 (mannose), and 0.85 (glucose), respectively. One hundred milligrams of p-bpa is able to dissolve in 3 ml of 0.3 M fructose solution at pH 7.98. Based on the results obtained, the behavior of p-bpa-monosaccharide complexes in vivo after injection of the complex solution is described.

Boron Compounds↗

PubMed1985

Effect of monosaccharides and ethyleneglycol on the interaction between Escherichia coli bacteria and Octyl-Sepharose.

Combined effects of monosaccharides and reduced surface tension of the medium were studied in relation to the hydrophobic binding of Escherichia coli bacteria, with and without mannose-specific structures. Hydrophobic binding was analyzed by hydrophobic interaction chromatography on Octyl-Sepharose. The results showed that ethyleneglycol, as well as mannose, reduced the hydrophobic interaction of the bacteria with mannose-specific structures. This effect was potentiated by combining ethyleneglycol and mannose. No other monosaccharides tested (galactose and fucose) had any effect on the hydrophobic interaction of bacteria with mannose-specific structures. These results further strengthen the hypothesis that the mannose-specific interaction of Escherichia coli bacteria is, at least in part, mediated by hydrophobic forces.

Adhesiveness↗