Sugar Interaction Research Articles

Selective Binding of Sugar to β‐Cyclodextrin: A Prototype for Sugar–Sugar Interactions in Water

Not only the hydrophobicity of the sugar to be complexed determines the strength of its bond to β‐cyclodextrin. Steric factors also play a large role. In water, aldopentoses are bound better as their hydrophobicity increases, but aldohexoses do not form complexes with β‐cyclodextrin even though some are clearly more hydrophobic than all the pentoses studied. This is the first example of a selective oligosugar–sugar interaction in water.

Determination of the association constant of monovalent mode protein—sugar interaction by capillary zone electrophoresis

Protein—sugar interaction was observed by capillary zone electrophoresis, using a few β-galactose-specific lectins and lactobionic acid as protein and sugar models, respectively. The lectin peaks were retarded in a concentration-dependent manner by addition of lactobionic acid in a carrier, and association constants of monovalent mode interactions could be obtained from t 1 (migration time of protein), t 2 (migration time of complex, obtainable as the migration time at the plateau) and the slope of the ( t - t 1) −1 vs. [S] −1 plots, where t and [S] are the migration of protein in the presence of lactobionic acid and the concentration of lactobionic acid, respectively. The values for Ricinus communis agglutinin, peanut agglutinin and soy bean agglutinin at pH 6.8 were 3.3 · 10 3, 9.1 · 10 2 and 1.1 · 10 2 1 mol −1, respectively. This method required only small amounts of protein samples and was reproducible. The amount of the sugar could be minimized under the conditions that the carrier was a buffer containing the sugar whereas the electrode solutions consisted only of the buffer

Molecular Mechanics Studies of Dinucleoside Methylphosphonates: Influence of Methylphosphonate and its Chirality on the Phosphodiester Conformation

Molecular mechanics studies are performed on single stranded as well as base paired forms of dinucleoside methylphosphonates comprising different base sequences for both the S- and R-isomers of methylphosphonate (MP). S-MP produces noticeable distortions in the geometry, locally at the phosphate center, and this enables the stereochemical feasibility of compact g- g- phosphodiester. Besides, it tends to perturb the conformations around the P-O3' and glycosyl bonds, causing minor variations in stacking interactions. In single stranded dinucleosides, the gain in adjacent base stacking interaction energies seems to be sufficient to overcome the barrier to P-O3' bond rotation arising due to S-MP...sugar interaction, and this results in transition to a compact phosphodiester (BI-type) from an initial extended phosphodiester (BII-type) conformation. Such a thing seems rather difficult in base pair constrained duplexes. Dinucleosides with R-MP behave analogous to normal phosphate duplexes as the methyl group is away from the sugar. It is found that dinucleoside methylphosphonates are energetically less favoured than the corresponding dinucleoside phosphates mainly due to the depletion of contributions from electrostatic attractive interactions involving the base and sugar with the methylphosphonate consequent to the nonionic nature of the latter. Neither S-MP nor R-MP seem to significantly alter the stereochemistry of duplex structure.

Effect of sucrose consumption on alcohol-induced impairment in male social drinkers

Two studies were conducted to examine the interaction between sucrose and ethanol in normal young fasting adult males. The first experiment employed a 3 (100 g sugar, 35 g sugar, 0 g sugar) x 3 (alcohol, placebo and sober) factorial design, which was carried out double-blind using aspartame to ensure that all the drinks were equally sweet. Subjects were tested for mood, memory, subjective intoxication and psychomotor performance at baseline and at times up to 3.5 h after ingestion of the drinks. An alcohol by sugar interaction was seen at 0.5 after drinking. Sugar attenuated alcohol intoxication at this time without influencing blood alcohol levels. Contrary to previous reports, the combination of alcohol and sugar failed to produce significant hypoglycemia, or any of the adverse behavioral effects associated with hypoglycemia, at later times after drink ingestion. The second experiment involved a simpler design, carried out single-blind in which the subjects receiving no sugar did not get aspartame. This was to rule out the possibility that aspartame was exacerbating alcohol intoxication instead of sugar attenuating it. The second experiment also showed that sugar can attenuate alcohol intoxication in fasting humans without altering blood alcohol levels significantly.

Metabolic Characteristics Associated with Starch, Protein, and Oil Deposition in Developing Maize Kernels

The physiological processes that control relative starch, protein, and oil concentration of maize(Zea mays L.) kernels are not well defined. In this study, associationS between Metabolic Characteristics of developing kernels and specific storage product accumulation in mature kernels were identified. In a field experiment, kernels of maize genotypes with widely divergent chemical composition were harvested 50 days post pollination (DPP) to compare starch, protein, and oil concentrations with enzyme activities, sugar,and aminoc acid levels of kernels harvested 20 DPP. Mature kernels starch concentrations were correlated with immature kernel sucrose concentrations and ADP‐glucose pyrophosphorylase activities. Amino acid concentrations in immature kernels were correlated with the activities of phosphoglucoisomerase, Phosphoglucomutase, pyrophosphate: fructose 6‐ phosphalt 1‐phosphotransferase, and aldolasea and with mature kernel protein concentrations, but negatively correlated with starch concentrations. Oil concentrations were positively correlated with mature embryo dry weights and with malate dehydrogenase activities in isolated embryos harvested 20 DPP. The results suggest a complex interaction of sugars and amino acids supplied to the kernel by the plant affecting enzyme activities and storage product accumulation the developing kernel. High‐starch genotypes supplied more sucrose to their kernels, had higher ADP‐glucose pyrophosphorylase activity, and greater starch accumulation. High‐protein genotypes supplied more amino acids to their kernels, and had enhanced expression of a number of enzymes that may contribute to the greater protein accumulation. These data suggest that nutrient supply interacts with expression of enzyme activities in developing kernels to determine starch and protein concentrations in mature kernels.

Chloride attachment negative-ion mass spectra of sugars by combined liquid chromatography and atmospheric pressure chemical ionization mass spectrometry

A method has been developed for the rapid determination of sugars, including molecular weight measurements, using high-performance liquid chromatography coupled with negative-ion, atmospheric-pressure chemical-ionization mass spectrometry. The chromatography was carried out on a 250 × 4 mm I.D. column packed with 7 μm NH 2-silica. The mobile phase consisted of a high percentage of methanol or acetonitrile with a small amount of chloroform. During the mass spectrometry, a strong base is formed from the polar solvent molecules by corona discharge, followed by ion—molecule reactions in the chemical ionization ion source ( e.g. the methoxy anion is formed from methanol). This strong base reacts with the chloroform, generating chloride ions, which in turn react with the neutral sugar molecules as they elute from the chromatograph. The chloride ion and sugar interactions yield chloride-attachment ions, which are further stabilized by successive collisions. In this method, authentic monosaccharides and some oligosaccharides show dominant quasi-molecular ions, [M + Cl] −, with little fragmentation, and it is particularly useful for the molecular weight determination of sugars.

Thermodynamic analysis of ligand binding to winged bean (Psophocarpus tetragonolobus) acidic agglutinin reveals its specificity for terminally monofucosylated H-reactive sugars.

The sugar-specific binding of N-dansylgalactosamine to WBA II (n = 2; Ka = 5.6 x 10(3) M-1; delta H = -21 kJ.mol-1; delta S = -21.3 J.mol-1.K-1) was utilized in substitution titrations for evaluating the association constants for the interaction of sugars with the lectin. An axial hydroxyl at C-4 and equatorial hydroxyls at C-3 and C-6 as in D-galacto configuration are crucial for binding. Both axial and equatorial hydroxyls are tolerated at C-2. Conformationally akin disaccharides such as lactose, N-acetyllactosamine, Gal beta 1-3GlcNAc, and Gal beta 1-3GalNAc show similar affinities. 2'-Fucosyllactose and H-disaccharide display 146 and 13 times stronger affinity over lactose and galactose, yet fucose by itself is devoid of activity. An interesting feature, noted for the first time, in protein-sugar interactions is the positive entropy change for the binding of 2'-fucosyllactose, suggesting that nonpolar interactions play an important role in stabilization of the lectin-sugar complex. 3-Fucosyllactose, lactodifucotetraose, lacto-N-fucopentaose II and III are inactive, whereas lacto-N-fucopentaose I has 14-fold lower affinity as compared with 2'-fucosyllactose. Conformational analysis indicates that the substitution at subterminal glucose or GlcNAc by L-fucose in either alpha 1-3 or alpha 1-4 linkage leads to its projection so as to sterically hinder the access of 3'-fucosyllactose, lactodifucotetraose, and lacto-N-fucopentaose II and III to the binding site of winged bean agglutinin II. Similarly the projection of alpha 1-3 linked Gal/GalNAc also leads to steric hindrance and hence prevents the binding of blood group A and B reactive sugars. Considering its unique specificity winged bean agglutinin II should be useful in the isolation and characterization of terminally monofucosylated H-reactive oligosaccharides from those that are difucosylated or internally fucosylated.

Human splenic galaptin: carbohydrate-binding specificity and characterization of the combining site

A galactose-binding lectin (galaptin) from human spleen has been purified to homogeneity by affinity chromatography on asialofetuin-Sepharose. The carbohydrate-binding specificity of galaptin has been investigated by analyzing the binding of galaptin to asialofetuin in the presence of putative inhibitors. An enzyme-linked immunosorbent assay (ELISA) was developed that involved adsorption of asialofetuin to microtiter plates. Galaptin bound to asialofetuin was detected with polyclonal rabbit anti-galaptin serum followed by goat anti-rabbit IgG-peroxidase conjugate. The concentrations of inhibitors giving 50% inhibition of galaptin binding relative to controls were graphically determined and normalized relative to galactose or lactose. These analyses revealed that galaptin has a combining site at least as large as a disaccharide. The disaccharides having non-reducing-terminal beta-galactosyl residues linked (1,3), (1,4), and (1,6) to Glc or GlcNAc are better inhibitors than free Gal. GalNAc, either free or glycosidically linked, appears to have no affinity for the lectin. The nitrophenyl galactosides are better inhibitors than methyl galactosides, indicating the occurrence of hydrophobic interactions. The data indicate that OH groups at C-4 and C-6 of Gal and the OH at C-3 of GlcNAc in Gal beta(1,4)GlcNAc are important for lectin sugar interaction. Our data support the hypothesis that endogenous receptors for galaptin are most likely lactosaminoglycan moieties.

Solute-Solvent and Water Activity of Small Carbohydrates: Application to the Study of Enzyme Stability in Aqueous Sugar Solutions

Abstract Viscometric constants of small carbohydrates are determined and interpreted in terms of specific hydration. Water activity of their saturated solutions is measured. Their effect on water structure is deduced from the deconvolution of the Raman bands in the OH region. The influence of water activity lowering of D-fructose, D-glucose and sucrose on initial lysozyme activity is studied. The effect of these sugars on the preservation of enzyme stability during the time is investigated for yeast alcohol dehydrogenase (YADH). Half-life time of YADH is controlled after the storage of the enzyme in different sugar and polyol solutions. Enzymatic results are in good agreement with the solute-solvent interactions of sugars and polyols in the aqueous medium. The sugar which provokes the most noticeable perturbation of water structure, i.e., D-fructose, causes the denaturation of the enzymes and acts as a destablizer.

Calorimetric studies on the interaction of sugars and polyols with the non-ionic surfactant TRITON-X-100 in aqueous solutions

The enthalpies of solution in the micellar state (Δ H s) for the non-ionic surfactant Triton-X-100 in water and aqueous solution of 1-M glucose, sucrose, mannitol and sorbitol were measured at 298.15 K and 308.15 K by a Tronac titration calorimeter. The enthalpy data were used to evaluate the heat capacities for the surfactant in the micellar state (Δ C p,s) at 303.15 K in the systems studied. The heat capacities of transfer for the surfactant in the micellar state (Δ C p,tr) from water to aqueous solutions of sugars and polyols were found to be negative. The value of (Δ C p,tr) for Triton-X-100 in the micellar state was more negative in glucose solution than in sucrose solution because of the relatively greater water-structure-making ability of glucose, whose hydroxyl groups have a better stereochemical compatibility with the structure of water than those of sucrose. Likewise, (Δ C p,tr) for the surfactant micelles is more negative in mannitol than sorbitol solution because of the better fitting of mannitol than sorbitol with the tridymite structure of water.

Interactions between cations and sugars. Part 5.—Enthalpy and entropy of interaction of the calcium ion with some aldopentoses and aldohexoses in water at 298.15 K

The enthalpies of interaction of ribose, arabinose, lyxose, xylose, glucose, mannose, galactose, talose and allose with CaCl2 and KCl have been determined in water at 298.15 K. From the free energies of interaction determined previously, the corresponding entropies have been calculated and an enthalpy–entropy compensation has been observed. The pair interaction parameters can be corrected for the anion–sugar interaction and for the non-specific cation–sugar interaction by comparing the Ca2+–sugar interactions either with the interactions between the non-complexed cation K+ and the same sugar or with the interactions between Ca2+ and an inactive epimer of the studied sugar. For the sugars that have specific interactions with Ca2+, namely ribose, talose, and allose, this allows the thermodynamic properties for the reaction of association of Ca2+ with the ‘ complexing ’ sequences of hydroxyl groups to be estimated as : ΔRG⊖≈– 2 kJ mol–1, ΔRH⊖≈– 17 kJ mol–1 and TΔRS⊖≈– 15 kJ mol–1.

Sugar interaction with cobalt-ammine cations. Synthesis, spectroscopic, and structural characterization of cobalt-pentammine and cobalt-tetrammine suga

Reactions of d-gluconic and d-glucuronic acids with cis-[CoCl 2(NH 3) 4]Cl and [CoCl(NH 3)5]Cl 2 have been investigated in aqueous solution, and solid complexes of the type [Co L(NH 3) 5]Cl 2.H 2O and [Co L(NH 3) 4] L.Cl.H 2O, (where L = d-gluconate or d-glucuronate anions) have been isolated and characterized by means of FT-IR 1H-NMR, and electron absorption spectroscopy. Spectroscopic evidence indicated that the sugar anion binds unidentately in the [CoL(NH 3) 5] 2+ (through the negatively charged carboxylate oxygen atom) and chelation in the [CoL(NH 3) 4] 2+ ( via the negatively charged OCO − oxygen atom in concert with other sugar donor atoms), resulting into a six-coordination with an octahedral geometry around the Co(III) ion. The strong sugar hydrogen bonding network is altered upon sugar-metal complexation, and the β-anomer sugar configuration is predominant both in the free d-glucuronic acid and in these cobalt-sugar complexes.

Interaction of metal ions with 6-oxopurine nucleotides. Part 2. X-Ray structures of ternary nickel(II) complexes with 2′-deoxyguanosine 5′-monophosphate or guanosine 5′-monophosphate

The ternary metal nucleotide complexes [Ni(en)1.3(H2O)1.4(H2O)2][Ni(5′-dGMP)2(en)0.7-(H2O)0.6(H2O)2]·7H2O (1) and [Ni(en)2(H2O)2][Ni(5′-GMP)2(H2O)4]·6H2O (2)(en = ethylenediamine, 5′-dGMP = 2′-deoxyguanosine 5′-monophosphate, 5′-GMP = guanosine 5′-monophosphate) have been prepared and their structures analyzed by X-ray diffraction methods. Both compounds crystallise in the space group C2221 with a= 8.810(1), b= 25.090(4), c= 21.084(1)A, and Z= 4 for (1) and a= 8.730(1), b= 25.691(4), c= 21.313(5)A, and Z= 4 for (2). The structures were deduced from the analogous CoIII complexes and refined by full-matrix least-squares methods to final R values of 0.087 and 0.131 for 1 211 and 954 reflections for (1) and (2) respectively. An interesting feature of the deoxyribonucleotide complex (1) is that en is not totally labilized from the metal centre on nucleotide co-ordination, as observed in corresponding ribonucleotide complexes. Apart from extensive intra- and inter-molecular hydrogen bonding, the structures are stabilized by significant intracomplex base–base and base–sugar interactions. The nucleotides in both complexes have an anti base, C(2′)-endo sugar pucker, and gauche–gauche conformation about the C(4′)–C(5′) bond.

Sugar interaction with biologically active cis-PtCl 2(NH 3) 2 (anticancer) and its inactive trans isomer

The interaction of d-glucuronic and d-gluconic acids with cis- and trans-ptCl 2 (NH 3) 2 (cisplatin and transplatin) has been investigated in aqueous solution and solid complexes of the type cis-[PtL(NH 3) 2L·H 2O and trans-[PtL 2(NH 3) 2]·H 2O, where L = d-glueuronate or d-gluconate anions, are isolated and characterized by means of Fourier transform-infrared and 1H-NMR spectroscopy, and molar conductivity and X-ray powder diffraction measurements. Spectroscopic and other evidence indicated that the sugar anions bind monodentately in trans-[PtL 2(NH 3) 2]·H 2O and bidentately in cis-[PtL(NH 3) 2]L·H 2O complexes through the carboxylate oxygen atoms and other sugar donor groups. The strong sugar intermolecular hydrogen-bonding network is altered to that of the sugar-OH ··· NH 3 (H 2O) ··· OH-sugar, upon platinum-ammine interaction. The d-glucuronate anion has the β-anomer configuration both in the free salt and in these platinum-sugar complexes.

ChemInform Abstract: Sugar Interaction with Uranium Ion. Synthesis, Spectroscopic and Structural Analysis of UO2‐Sugar Complexes Containing D‐Glucuronate Moiety.

AbstractThe 1:1 or 1:2 reaction of hydrated uranyl salts or uranyl acetate with D‐glucuronic acid in aqueous solution lead to solid complexes of the type (I) and (II), resp., which are characterized by Ft‐IR and 1H NMR spectroscopy.

ChemInform Abstract: Sugar Interaction with Silver Ion. Synthesis, Syectroscopic and Structural Analysis of Silver‐ Glucuronate Compounds.

AbstractInteraction between D‐glucuronic acid and Ag(I) ion using Ag nitrate or Ag carbonate in aqueous solution are studied.

Sugar interaction with silver ion. Synthesis, spectroscopic and structural analysis of silver-glucuronate compounds

Interaction between the D-glucuronic acid and the Ag(I) ion has been studied, in aqueous solution and solid compounds of the type Ag(D-glucuronic)NO 3 and Ag(D-glucuronate) have been isolated and characterized, by means of 1H NMR and FTIR spectroscopy. Spectroscopic and other evidence indicated that the Ag(I) ion in Ag(D-glucuronic)NO 3 compound binds to two sugar moieties via non-ionized carboxyl O6′ atoms, resulting into a linear coordination around silver ion with no direct interaction between the nitrate anion and the Ag(I) ion. On the other hand, the Ag(D-glucuronate) salt is a dimeric with each silver ion binding to two sugar anions through O6 and O6′ carboxyl oxygen atoms with a linear binding around each Ag(I) ion. The strong sugar hydrogen bonding network is rearranged upon metalation and the β-anomer sugar conformation is dominating both in the free acid and in these silver-sugar compounds.

Sugar interaction with uranium ion. Synthesis, spectroscopic and stmctural analysis of UO 2-sugar complexes containing D-glucuronate moiety

Interaction between D-glucuronic acid and hydrated uranyl salts has been studied in aqueous solution and solid complexes of the type UO 2(D- glucuronate)X·2H 20 and UO 2(D-glucuronate) 2·2H 2O, where X = CI −, Br − or NO 3 −, are isolated and characterized by means of FT-IR and proton-NMR spectroscopy. On comparison with the structurally identified Ca(D-glucuronate)Br·3H 2O compound, it is concluded that the UO 2 2+ cation binds to two D- glucuronate moieties in uranylsugar complexes via O6, O5 oxygen atoms (ionized carboxyl group) of the first and O6′, 04 (non-ionized carboxyl group) of the second sugar moiety, whereas in the UO 2(D- glucuronate) 2·2H 2O salt the uranyl ion is bonded to two sugar anions through O6, O6′ oxygen atoms of the ionized carboxyl group, resulting in a six- coordination geometry around the uranium ion. The strong intermolecular hydrogen bonding network of the free acid is rearranged upon sugar metalation and the sugar moiety showed β-anomer conformation both in the free acid and in these uranylsugar complexes.

Sugar interaction with calcium ion. synthesis and vibrational spectra of crystalline β-d-fructose and its calcium halide adducts

D-fructose reacts with the calcium ion to give complexes of the type Ca(δ- d-fructose)Cl 2-2H 2O, Ca(⨿- D-fructose) 2 Cl 2·3H 2O and Ca(⨿- d-fructose)Br 2-2H 2O. The infrared spectra of the free⨿- d-fructose and its calcium compounds are examined and a correlation between the spectral changes and the coordination sites involved has been established. Structurally known Ca(⨿- d-fructose)Cl 2· 2H 2O and its isomorphous Ca(⨿- d-fructose)Br 2·2H 2O showed that each calcium ion is seven-coordinated, binding to three symmetry related fructose molecules through O(2), O(3) of the first, O(4), O(5) of the second, and O(1) of the third molecule as well as to two water molecules, whereas in the Ca(⨿- d-fructose) 2Cl 2 · 3H 2O compound the calcium cation is eight coordinated, binding to two sugar molecules via O(1), O(4), and O(5) of each sugar moiety, as well as to two water molecules. Spectroscopic evidence presented here indicated that the two structurally dissimilar 1:1 and 2:1 calcium chloride adducts are spectrally different, while the 1:1 calcium chloride and the bromide complexes have virtually identical infrared spectra. The rearrangement of the strong hydrogen bonding network of the free sugar occurred upon metalation. Furthermore, the band assignments in the OH stretching region have been correlated with the sugar intermolecular hydrogen-bonding O  O distances reported from the x-ray and the neutron diffraction measurements.

The preferred conformation of 2-fluoro-2-deoxy β-D-mannopyranosyl fluoride. An X-ray crystallographic and 2-dimensional proton nuclear magnetic resonance study

The preferred conformation of 2-fluoro-2-deoxy β-D-mannopyranosyl fluoride has been determined in the solid state by X-ray crystallography and in aqueous solution by 2-dimensional J-resolved proton nuclear magnetic resonance. Crystals of 2-fluoro-2-deoxy β-D-mannopyranosyl fluoride are monoclinic, a = 4 10.9150(8), b = 4 4.9079(4), c = 4 6.9902(6) Å, β = 105.158(4)°, Z = 2, space group P21. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.028 and Rw = 0.031 for 797 reflections with I ≥ 3σ(I). The sugar ring was present in an essentially undistorted 4C1 chair conformation. Weak, but significant interactions, presumably hydrogen bonding of the type OH … F and CH … F, are observed within the crystal lattice. Coupling constants observed in the proton nmr were consistent only with a 4C1 chair conformation in solution. These observations are briefly discussed in terms of recent findings concerning the interaction of fluorodeoxy sugars with enzymic binding sites.