The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform
Willy Malaisse - One of the best experts on this subject based on the ideXlab platform.
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Hexose metabolism in pancreatic islets: Effect of D-glucose upon D-fructose metabolism
Molecular and Cellular Biochemistry, 1999Co-Authors: Olivier Scruel, Abdullah Sener, Willy MalaisseAbstract:In the light of recent findings on the effect of D-glucose upon D-fructose phosphorylation by human B-cell glucokinase, the influence of the Aldohexose upon the metabolism of the ketohexose was investigated in rat pancreatic islets. D-glucose, although slightly decreasing D-[5-3H]fructose utilization, augmented the oxidation of the ketohexose, indicating that the Aldohexose stimulates preferentially the oxidative, as distinct from anaerobic, modality of glycolysis. Such was not the case in parotid cells, taken as representative of functionally nonglucose-responsive cells. In the islets exposed to D-fructose, D-glucose also decreased the fractional contribution of the pentose shunt to the generation of CO2 and D-glyceraldehyde 3-phosphate from the ketohexose, and increased the inflow into the Krebs cycle of dicarboxylic metabolites relative to that of fructose-derived acetyl-CoA. This glucose-induced remodeling of D-fructose metabolism may optimize the insulin secretory response of islet cells to these hexoses, e.g. after food intake.
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Does phosphoglucoisomerase display anomeric specificity or selectivity towards α-d-glucose 6-phosphate? An assessment by two-dimensional phase-sensitive 31P exchange spectroscopy (EXSY) n.m.r
Biochemical Journal, 1993Co-Authors: François Kayser, F Malaisse-lagae, Monique Biesemans, Rudolph Willem, Willy MalaisseAbstract:The study by two-dimensional phase-sensitive 31P exchange spectroscopy (EXSY) n.m.r. of hexose 6-phosphates interconversion in the reaction catalysed by yeast phosphoglucoisomerase reveals that the enzyme displays anomeric selectivity, rather than specificity, towards alpha-D-glucose 6-phosphate. Indeed, beta-D-glucose 6-phosphate participates for about 20% to the total and direct conversion of the Aldohexose into oxohexose ester.
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Does phosphoglucoisomerase display anomeric specificity or selectivity towards alpha-D-glucose 6-phosphate? An assessment by two-dimensional phase-sensitive 31P exchange spectroscopy (EXSY) n.m.r.
The Biochemical journal, 1993Co-Authors: François Kayser, Monique Biesemans, Rudolph Willem, F Malaisse-lagae, Willy MalaisseAbstract:The study by two-dimensional phase-sensitive 31P exchange spectroscopy (EXSY) n.m.r. of hexose 6-phosphates interconversion in the reaction catalysed by yeast phosphoglucoisomerase reveals that the enzyme displays anomeric selectivity, rather than specificity, towards alpha-D-glucose 6-phosphate. Indeed, beta-D-glucose 6-phosphate participates for about 20% to the total and direct conversion of the Aldohexose into oxohexose ester.
François Kayser - One of the best experts on this subject based on the ideXlab platform.
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Does phosphoglucoisomerase display anomeric specificity or selectivity towards α-d-glucose 6-phosphate? An assessment by two-dimensional phase-sensitive 31P exchange spectroscopy (EXSY) n.m.r
Biochemical Journal, 1993Co-Authors: François Kayser, F Malaisse-lagae, Monique Biesemans, Rudolph Willem, Willy MalaisseAbstract:The study by two-dimensional phase-sensitive 31P exchange spectroscopy (EXSY) n.m.r. of hexose 6-phosphates interconversion in the reaction catalysed by yeast phosphoglucoisomerase reveals that the enzyme displays anomeric selectivity, rather than specificity, towards alpha-D-glucose 6-phosphate. Indeed, beta-D-glucose 6-phosphate participates for about 20% to the total and direct conversion of the Aldohexose into oxohexose ester.
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Does phosphoglucoisomerase display anomeric specificity or selectivity towards alpha-D-glucose 6-phosphate? An assessment by two-dimensional phase-sensitive 31P exchange spectroscopy (EXSY) n.m.r.
The Biochemical journal, 1993Co-Authors: François Kayser, Monique Biesemans, Rudolph Willem, F Malaisse-lagae, Willy MalaisseAbstract:The study by two-dimensional phase-sensitive 31P exchange spectroscopy (EXSY) n.m.r. of hexose 6-phosphates interconversion in the reaction catalysed by yeast phosphoglucoisomerase reveals that the enzyme displays anomeric selectivity, rather than specificity, towards alpha-D-glucose 6-phosphate. Indeed, beta-D-glucose 6-phosphate participates for about 20% to the total and direct conversion of the Aldohexose into oxohexose ester.
Brad Bendiak - One of the best experts on this subject based on the ideXlab platform.
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Direct evidence for the ring opening of monosaccharide anions in the gas phase: photodissociation of Aldohexoses and Aldohexoses derived from disaccharides using variable-wavelength infrared irradiation in the carbonyl stretch region
Carbohydrate Research, 2011Co-Authors: Darin J. Brown, Sarah E. Stefan, Giel Berden, Jeffrey D. Steill, Jos Oomens, John R. Eyler, Brad BendiakAbstract:All eight D-Aldohexoses and Aldohexoses derived from the non-reducing end of disaccharides were investigated by variable-wavelength infrared multiple-photon dissociation (IRMPD) as anions in the negative-ion mode. Spectroscopic evidence supports the existence of a relatively abundant open-chain configuration of the anions in the gas phase, based on the observation of a significant carbonyl absorption band near 1710 cm(-1). The abundance of the open-chain configuration of the Aldohexose anions was approximately 1000-fold or greater than that of the neutral sugars in aqueous solution. This provides an explanation as to why it has not been possible to discriminate the anomeric configuration of Aldohexose anions in the gas phase when derived from the non-reducing sugar of a disaccharide. Evidence from photodissociation spectra also indicates that the different Aldohexoses yield product ions with maximal abundances at different wavelengths, and that the carbonyl stretch region is useful for differentiation of sugar stereochemistries. Quantum-chemical calculations indicate relatively low energy barriers to intramolecular proton transfer between hydroxyl groups and adjacent alkoxy sites located on open-chain sugar anions, suggesting that an ensemble of alkoxy charge locations contributes to their observed photodissociation spectra. Ring opening of monosaccharide anions and interconversion among configurations is an inherent property of the ions themselves and occurs in vacuo independent of solvent participation. (C) 2011 Elsevier Ltd. All rights reserved.
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end group determination of oligosaccharides a gas chromatography mass spectrometry mass spectrometry method for distinguishing between all d Aldohexoses and d ketohexoses
Carbohydrate Research, 2000Co-Authors: Brad Bendiak, Tammy T. FangAbstract:Abstract A method for end-group determination of oligosaccharides is described, which involves conversion of the reducing monosaccharide into a 1-deoxy-1-hydrazinohexitol heptaacetate (Aldohexoses) or an epimeric pair of 2-deoxy-2-hydrazinohexitol heptaacetates (2-ketohexoses). Products are linear and unique to each Aldohexose or ketohexose. Methods are reported for separation of all stereoisomers of the derivatives on single columns by gas chromatography. Gas chromatography–mass spectrometry/mass spectrometry with electron-impact ionization enabled the 1-deoxy-1-hydrazinohexitol heptaacetates and 2-deoxy-2-hydrazinohexitol heptaacetates to be independently identified in each others presence. Chemical-ionization mass spectrometry/mass spectrometry permitted derivatives to be identified in subpicomolar quantities. The non-acetylated compounds could also be identified as their hydrochlorides by 1H NMR spectroscopy.
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End-group determination of oligosaccharides: a gas chromatography-mass spectrometry/mass spectrometry method for distinguishing between all D-Aldohexoses and D-ketohexoses.
Carbohydrate Research, 2000Co-Authors: Brad Bendiak, Tammy T. FangAbstract:Abstract A method for end-group determination of oligosaccharides is described, which involves conversion of the reducing monosaccharide into a 1-deoxy-1-hydrazinohexitol heptaacetate (Aldohexoses) or an epimeric pair of 2-deoxy-2-hydrazinohexitol heptaacetates (2-ketohexoses). Products are linear and unique to each Aldohexose or ketohexose. Methods are reported for separation of all stereoisomers of the derivatives on single columns by gas chromatography. Gas chromatography–mass spectrometry/mass spectrometry with electron-impact ionization enabled the 1-deoxy-1-hydrazinohexitol heptaacetates and 2-deoxy-2-hydrazinohexitol heptaacetates to be independently identified in each others presence. Chemical-ionization mass spectrometry/mass spectrometry permitted derivatives to be identified in subpicomolar quantities. The non-acetylated compounds could also be identified as their hydrochlorides by 1H NMR spectroscopy.
Takeo Ohsaka - One of the best experts on this subject based on the ideXlab platform.
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enhanced oxidation of Aldohexose and aldopentose on hg adatom modified au electrode in alkaline aqueous solution
Electroanalysis, 2005Co-Authors: Futoshi Matsumoto, Masahiro Harada, Nobuyuki Koura, Takeyoshi Okajima, Takeo OhsakaAbstract:The electrochemical behavior of Aldohexose and aldopentose monosaccharides was examined on Hg adatom-modified and bare Au electrodes in alkaline aqueous solution using cyclic voltammetry. For the bare Au electrode, the oxidation peak currents are dependent on hydroxyl group configuration on the monosaccharides. On the other hand, for the Hg adatom-modified Au electrode, the actual oxidation peak currents were similar for all monosaccharides other than glucose. Dispersion of Hg adatoms on the Au surface led to diminishment of configurational differences between monosaccharides as well as enhancement of oxidation peak current.
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Enhanced Oxidation of Aldohexose and Aldopentose on Hg Adatom‐Modified Au Electrode in Alkaline Aqueous Solution
Electroanalysis, 2005Co-Authors: Futoshi Matsumoto, Masahiro Harada, Nobuyuki Koura, Takeyoshi Okajima, Takeo OhsakaAbstract:The electrochemical behavior of Aldohexose and aldopentose monosaccharides was examined on Hg adatom-modified and bare Au electrodes in alkaline aqueous solution using cyclic voltammetry. For the bare Au electrode, the oxidation peak currents are dependent on hydroxyl group configuration on the monosaccharides. On the other hand, for the Hg adatom-modified Au electrode, the actual oxidation peak currents were similar for all monosaccharides other than glucose. Dispersion of Hg adatoms on the Au surface led to diminishment of configurational differences between monosaccharides as well as enhancement of oxidation peak current.
Rudolph Willem - One of the best experts on this subject based on the ideXlab platform.
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Does phosphoglucoisomerase display anomeric specificity or selectivity towards α-d-glucose 6-phosphate? An assessment by two-dimensional phase-sensitive 31P exchange spectroscopy (EXSY) n.m.r
Biochemical Journal, 1993Co-Authors: François Kayser, F Malaisse-lagae, Monique Biesemans, Rudolph Willem, Willy MalaisseAbstract:The study by two-dimensional phase-sensitive 31P exchange spectroscopy (EXSY) n.m.r. of hexose 6-phosphates interconversion in the reaction catalysed by yeast phosphoglucoisomerase reveals that the enzyme displays anomeric selectivity, rather than specificity, towards alpha-D-glucose 6-phosphate. Indeed, beta-D-glucose 6-phosphate participates for about 20% to the total and direct conversion of the Aldohexose into oxohexose ester.
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Does phosphoglucoisomerase display anomeric specificity or selectivity towards alpha-D-glucose 6-phosphate? An assessment by two-dimensional phase-sensitive 31P exchange spectroscopy (EXSY) n.m.r.
The Biochemical journal, 1993Co-Authors: François Kayser, Monique Biesemans, Rudolph Willem, F Malaisse-lagae, Willy MalaisseAbstract:The study by two-dimensional phase-sensitive 31P exchange spectroscopy (EXSY) n.m.r. of hexose 6-phosphates interconversion in the reaction catalysed by yeast phosphoglucoisomerase reveals that the enzyme displays anomeric selectivity, rather than specificity, towards alpha-D-glucose 6-phosphate. Indeed, beta-D-glucose 6-phosphate participates for about 20% to the total and direct conversion of the Aldohexose into oxohexose ester.