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PubMed1995

Disaccharide analysis of chondroitin sulphate in human gingival crevicular fluid using high-performance liquid chromatography.

Gingival crevicular fluid (GCF) was collected into capillary tubes from healthy gingiva and sites of advanced periodontitis. Following digestion with Pronase E, the glycosaminoglycans were isolated by successive precipitation into 5% cetylpyridinium chloride and 95% ethanol. Unsaturated disaccharide isomers of chondroitin sulphate, obtained following chondroitinase ACII digestion, were analysed by high-performance liquid chromatography. Chondroitin sulphate was found in all GCF samples, with greater amounts in patients with periodontal disease than at control sites with a relatively healthy periodontium. The predominant isomer in the periodontal diseased group was delta Di-4S, while that in the control group and serum samples was delta Di-0S. Comparison of the relative proportions of the unsaturated disaccharides in GCF with previously reported values for alveolar bone, cementum, gingiva and periodontal ligament, as well as for serum, indicates that the chondroitin sulphate present in GCF of patients with periodontal disease originated from the mineralized connective tissues of the periodontium, notably alveolar bone, possibly with some contributions from soft connective tissues of gingiva and periodontal ligament and from serum.

Adult↗
PubMed1984

X-ray analysis of 3-O-(6-O-acetyl-2,4-diazido-3-O-benzyl-2,4-dideoxy-alpha-D-gl glucopyranosyl)-1,6-anhydro-2,4-diazido-2,4-dideoxy-beta-D- glucopyranose, a disaccharide having an unusual alpha-D-(1----3) linkage.

The crystal structure of 3-O-(6-O-acetyl-2,4-diazido-3-O-benzyl-2,4-dideoxy-alpha-D- glucopyranosyl)-1,6-anhydro- 2,4-diazido-2,4-dideoxy-beta-D-glucopyranose, C21H24N12O7, mol. wt. 556.5, was investigated by X-ray analysis. The disaccharide crystallizes in the triclinic space group P1, with a = 889.3(5), b = 869.6(5), and c = 999.5(6) pm, and alpha = 105.83(4) degrees, beta = 116.22(4) degrees, gamma = 88.42(4) degrees, Z = 1, and rho = 1.394 g.cm-3. Phase determination failed with direct methods, but, as the 1,6-anhydride component of the molecule was already known from a previous structure analysis, the vector-search method could be applied in solving the structure. Diffractometer data were refined to an R value of 0.063 (Rw = 0.080) for 2102 observed reflections. The anhydro-bridged system has a distorted 1C4(D) conformation, in agreement with that of other anhydropyranoses so far investigated. A comparison shows that, for the specific kind of distortion, mainly the anti-reflex effect is responsible, whereas 1,3-diaxial interactions have a minor influence. The nonbridged ring adopts an almost perfect 4C1(D) conformation. The anomeric effect is observed in both of the sugar-ring systems in terms of bond-length shortening. The disaccharide has an alpha-D-Glc-4C1-(1a----3e)-D-Glc-1C4 glycosidic linkage. No previous X-ray investigation of a compound of this type is known. The pyranoid rings are almost perpendicular to each other. The phi, psi angles of the glycosidic linkage are +78.1(5) and -86.0(4) degrees.(ABSTRACT TRUNCATED AT 250 WORDS)

Crystallography↗
PubMed1985

N.m.r. studies of the disulphated disaccharide obtained by degradation of bovine lung heparin with nitrous acid.

The disulphated disaccharide IdoA(2SO3)-anManOH(6SO3) was prepared from bovine lung heparin by treatment with nitrous acid followed by borohydride reduction. The 1H- (400 MHz) and 13C-n.m.r. (100 MHz) spectra of this disaccharide derivative have been assigned completely using homonuclear spin-decoupling experiments, 13C-1H correlations, and a COSY-45 two-dimensional homonuclear correlation experiment. The 3JH,H values show that the IdoA(2SO3) residue exists in a single conformation throughout the temperature range 20-90 degrees.

Animals↗
PubMed1987

A simple strategy for changing the regioselectivity of glycosidase-catalysed formation of disaccharides.

The regioselectivity of glycosidase-catalysed formation of disaccharides can be changed by using alpha- or beta-glycosyl acceptors with various aglycons. The preponderant formation of other than (1----6) linkages can be effected with glycosidases which normally give (1----6) linkages. Thus, an alpha-D-galactosidase can be induced to catalyse the formation mainly of alpha-(1----2)-, alpha-(1----3), or alpha-(1----6)-linked digalactosides. Both the structure of the aglycon and the configuration of the glycosidic linkage can have a pronounced influence on the regioselectivity of disaccharide formation. Enzymic syntheses, in yields of 20-30%, are described of alpha-D-Galp-(1----3)-alpha-D-Galp-OMe, beta-D-Galp-(1----3)-beta-D-Galp-OMe, beta-D-Galp-(1----6)-alpha-D-Galp-OMe, alpha-D-Manp-(1----2)-alpha-D-Manp-OMe, alpha-D-Manp-(1----6)-alpha-D-Manp-OMe, alpha-D-Galp-(1----2)-alpha-D-Galp-OPhNO2-o, alpha-D-Galp-(1----3)-alpha-D-Galp-OPhNO2-p, alpha-D-Manp-(1----2)-alpha-D-Manp-OPhNO2-p, and alpha-D-Manp-(1----2)-alpha-D-Manp-(1----2)-alpha-D-Manp+ ++-OMe. Soluble and immobilised enzymes have been used.

Carbohydrate Conformation↗
PubMed1989

Preparation and characterization of antibodies against 6-O-alpha-D-xylopyranosyl-beta-D-glucopyranose (beta-isoprimeverose), the disaccharide unit of xyloglucan in plant cell-walls.

The p-aminophenyl beta-glycoside of 6-O-alpha-D-xylopyranosyl-D-glucopyranose (isoprimeverose), the disaccharide unit of plant xyloglucan, was coupled to bovine serum albumin, and the resulting glycoconjugate was used as an immunogen for the immunization of a rabbit. The immunochemical specificities of the rabbit antiserum raised against the glycoconjugate were characterized by immunodiffusion, quantitative precipitation, and hapten inhibition. After removal of anti-bovine serum albumin antibodies, the antiserum exhibited a specificity for the introduced disaccharide unit of the artificial antigen. The antibody-combining site was also shown to recognize the aglycon portion of the introduced hapten. The antiserum interacted with some xyloglucans, such as those from tamarind seed and the cell wall of pea stem. beta-Isoprimeverose and alpha-D-xylopyranosides were good inhibitors of the xyloglucan-antibody precipitation system, indicating that the antibodies recognize the beta-isoprimeverose unit of the xyloglucan.

Antibodies↗
PubMed1990

Formation of disaccharides related to heparin and heparan sulfate by chemical modification of maltose.

Maltose has been converted into 4-O-(2-amino-2-deoxy-alpha-D-glucopyranosyl)-L-idopyranuronic acid, 4-O-(2-amino-2-deoxy-alpha-D-glucopyranosyl)-D-glucopyranose, and 4-O-alpha-D-glucopyranosyl-L-idopyranose, the first two disaccharides being related structurally to biose sequences in heparin and heparan sulfate. Used as the starting material was a major product of the kinetic acetonation of maltose, namely, 2,3:5,6-di-O-isopropylidene-4-O-(4,6-O-isopropylidene-alpha-D-glucopyran osyl)-aldehydo-D-glucose dimethyl acetal. It was subjected to a sequence of transformation that included the introduction of a 2'-amino-2'-deoxy function into the glucosyl group, the inversion of C-5 in the glucose residue to give the L-ido configuration, oxidation at position 6, and cyclisation of the acyclic dimethyl acetal to give the desired pyranuronic acid. In the formation of the latter, the 5-O-levulinoyl substituent was found to be less prone to acyl migration to O-6 than more conventional ester groups. The relative acid labilities of the O-isopropylidene and dimethyl acetal groups are compared, and conformations of the acyclic residues of some disaccharide derivatives are discussed.

Carbohydrate Conformation↗
PubMed1992

GLC-MS of reduced, acetylated, and methylated (2----4)- and (2----8)-linked disaccharides of 3-deoxy-D-manno-octulopyranosonic acid (Kdo).

Synthetic alpha- and beta-(2----4)- and alpha- and beta-(2----8)-linked disaccharides of 3-deoxy-D-manno-octulopyranosonic acid (Kdo), of which the synthesis of the beta-(2----4)-linked compound is described here, were used to develop a simple GLC-MS method for the determination of their anomeric configuration. The GLC and GLC-MS data for the reduced and acetylated or methylated derivatives of the above compounds indicate the alpha-linked synthetic disaccharides to be identical to those isolated from bacterial lipopolysaccharides.

Acetylation↗
PubMed1993

Synthesis of a terminal A-B-C disaccharide fragment of flambamycin, curamycin, and avilamycin.

Methyl 2,6-dideoxy-4-O-[2,6-dideoxy-4-O-(3,5-dichloro-4-hydroxy-2-methoxy-6- methylbenzoyl)-beta-D-arabino-hexopyranosyl]-alpha-D-arabino-he xopyranoside (25) corresponds to an A-B-C disaccharide subunit of the title antibiotics. It was synthesized from suitably protected monosaccharide and aromatic precursors. The readily available 4,6-O-benzylidene-1,2-O-(R)-propylidene-alpha-D-glucopyranose was converted in six steps into 2-O-acetyl-4-O-benzoyl-3-O-benzyl-6-deoxy-alpha-D-glucopyranosyl bromide, which was condensed with methyl 3-O-benzyl-2,6-dideoxy-alpha-D-arabino-hexopyranoside in the presence of mercury(II) cyanide. Methyl 4-O-(2-O-acetyl-4-O-benzoyl-3-O-benzyl-6-deoxy-beta- D-glucopyranosyl)-3-O-benzyl-2,6-dideoxy-alpha-D-arabino-hexopyranosi de was converted either into methyl 2,6-dideoxy-4-O-(6-deoxy-beta-D- glucopyranosyl)-alpha-D-arabino-hexopyranoside by removal of the protective groups or into methyl 3-O-benzyl-4-O-(3-O-benzyl-2,6-dideoxy-beta-D-arabino-hexopyranosyl)-2,6 - dideoxy-alpha-D-arabino-hexopyranoside (22) by selective deacetylation, Barton deoxygenation, and Zemplén debenzoylation. Disaccharide 22 was deprotonated with butyllithium and treated with 4-benzyloxy-3,5-dichloro-2-methoxy-6-methylbenzoyl chloride to give the title compound 25 after hydrogenolysis.

Anti-Bacterial Agents↗
PubMed1993

Synthesis of the C'D' disaccharide of aureolic acid.

Arylbis(arylthio)sulfonium salts have been used to activate glycals towards nucleophilic addition to form principally 2-deoxy-beta-glycosides. This method was applied to the synthesis of the 2-(methylphenylthio)-2'-phenylthio derivative (22) of methyl O-(4-O-benzyl-2,6-dideoxy-beta-D-arabino- hexopyranosyl)-(1-->3)-3,4-di-O-benzyl-2,6-dideoxy-2,6-beta-D-arabino- hexopyranoside, the C'D' ring analog of an aureolic acid disaccharide. The condensation of 1,5-anhydro-2,6-dideoxy-D-arabino-hex-1-enitol with methanol in the presence of the phenylbis(phenylthio)sulfonium salt resulted in formation of the first beta-glycoside linkage. The methyl 6-deoxyglucoside obtained was deprotected at HO-3 to give the 2-thiophenyl-substituted 2,6-dideoxy-beta-glucoside. This was coupled with 1,5-anhydro-3,4-di-O-benzyl-2-deoxy-D-arabino-hex-1-enitol in the presence of 4-methylphenyl[bis(4-methylphenyl)thio]sulfonium salt to give the (1-->3)-linked disaccharide 22. Finally, desulfurization of 22 using WII Raney nickel generated the required 2,2'-dideoxydisaccharide.

Carbohydrate Sequence↗
PubMed1994

Highly stereoselective synthesis of alpha,beta-linked, nonreducing disaccharides related to tunicamycin.

3,4,6-Tri-O-benzoyl-2-(benzoyloxyimino)-2-deoxy-alpha-D-arabino-++ +hexopyranosy l bromide (2) reacts with the O-protected 2-deoxy-2-phthalimido-beta-D-galactosamines 3 and 4 in the presence of silver triflate and sym-collidine at -78 degrees C, to give alpha,beta-(1-->1)-linked disaccharides 6a and 7a with an excellent selectivity. The 2-oxyimino function was stereospecifically converted into a 2-acetamido group by use of the LiBH4-Me3SiCl-THF reductive species, furnishing, after acetylation, the alpha-D-GlcNAc-(1-->1)-beta-D-GalNPhth nonsymmetrical, trehalose type disaccharides 13 and 14 related to tunicamycin (1, part A). Similarly, alpha-D-GlcNAc-(1-->1)-beta-D-GlcNPhth (15) was prepared, starting from 2 and 5. The factors governing the stereoselectivity of the glycosylation reactions were determined.

Carbohydrate Conformation↗
PubMed1994

Alpha-(1-->2)-, and alpha-(1-->3)-, and alpha-(1-->6)-linked thioglycosidic disaccharides: syntheses and anti-HIV testing of thiokojibiose octaacetate, thionigerose, and thioisomaltose.

The syntheses of several alpha-linked thioglycosidic disaccharides are described, including thiokojibiose octaacetate (1), thionigerose (2), and thioisomaltose (3). The title compounds were synthesized by coupling 2,3,4,6-tetra-O-acetyl-1.5-acetyl-1-thio-alpha-D-glucopyranose (4) with either 1,3,4,6-tetra-O-acetyl-2-O-trifluoromethylsulfonyl-beta-D-manno pyr anose (7), 1,2:5,6-di-O-isopropylidene-3-O-trifluoromethylsulfonyl-alpha-D-++ +allofuranose (15), or methyl 2,3,4-tri-O-acetyl-6-deoxy-6-iodo-alpha-D-glucopyranoside (17), respectively. Thiokojibiose octaacetate in turn was converted to 3,4,6-tri-O-acetyl-2-S-(2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl)-2 -thio-alpha-D-glucopyranosyl bromide (9), which was used to obtain several related disaccharides and one trisaccharide. All of the compounds, including thiomaltose and thiotrehalose, which were resynthesized by known methods, were tested for their anti-HIV activity in either CEM or MT-2 cells. Anti-HIV activity was noted only with thiokojibiose octaacetate and its 1-thio analogue (14), which had IC50 values of 51 and 48 micrograms/mL in CEM cells, respectively.

Antiviral Agents↗
PubMed1996

A convenient new pathway for stereospecific epimerization of monosaccharide moieties in disaccharides.

The disaccharides benzyl 4,6-O-benzylidene-2-O-alpha-D-mannopyranosyl-beta- D-glucopyranoside (2), 6-O-beta-D-galactopyranosyl-1,2:3,4-di-O-isopropylidene-alpha-D- galactopyranose (4), and phenyl 4-O-beta-D-galactopyranosyl-1-thio-beta-D-glucopyranoside (7) were selectively acetalated with chloral-dicyclohexylcarbodiimide in a nonclassical pathway. During acetalation, the D-mannopyranosyl moiety of the disaccharide 2 and the unprotected beta-D-galactopyranosyl moieties of 4 and 7 were epimerized at their 3-positions, generating D-altro- and D-gulo-pyranosyl moieties, respectively.

Carbohydrate Conformation↗
PubMed1993

Separation and determination of glycosaminoglycan disaccharides by micellar electrokinetic capillary chromatography for studies of pelt glycosaminoglycans.

Capillary electrophoresis based on cetyltrimethylammonium bromide micellar electrokinetic capillary chromatography (MECC) was developed for the separation and determination of glycosaminoglycan (GAG) disaccharide units without derivatization. The influence of changes in several separation conditions was studied, and the separation mechanisms are discussed. Tests of repeatability and linearity were performed for qualitative and quantitative evaluation of the method. The described procedure gives a rapid and efficient determination of GAG disaccharides. Samples of chondroitin sulphates and mink skin were treated with proteases, and the extent of protein cleavage was followed by free zone capillary electrophoresis. The result of the chondroitinase ABC treatment following the protease treatment was evaluated by the MECC method.

Animals↗
PubMed1994

Capillary zone electrophoresis assay of the uridine diphosphate N-acetylmuramyl peptide precursors and the disaccharide pentapeptide derivative of bacterial cell wall peptidoglycan.

Uridine diphosphate N-acetylmuramyl peptide (EDP-MurNac) precursors and disaccharide pentapeptide of bacterial cell wall peptidoglycan were extracted from Enterobacter colacae cells and examined by capillary zone electrophoresis. Five UDP-MurNac derivatives with dibromopropamidine isethionate as the internal standard, and disaccharide pentapeptide with pyrimethamine as the internal standard, were successfully and rapidly analysed by using a fused-silica capillary and sodium phosphate buffer in methanol as the organic modifier at appropriate pH. Accurate quantitation was also achieved. The method provides the potential to investigate quantitatively the effect of antibacterials on the biosynthesis of peptidoglycan and to determine the relative cellular concentrations of the murein precursors within the cell cycle.

Cell Cycle↗
PubMed2004

Synthesis of a disaccharide fragment of rhamnogalacturonan II.

A disaccharide portion of the A-side chain of the rhamnogalacturonan II oligosaccharide has been prepared. Glycosylation of methyl (methyl 3,4-O-isopropylidene-alpha-D-galactopyranosid)uronate with p-tolyl 2,3-di-O-acetyl-3-C-(benzyloxymethyl)-1-thio-alpha/beta-D-erythrofuranoside was carried out using N-iodosuccinimide as promoter and silver trifluoromethanesulfonate as catalyst. Removal of the protecting groups gave the beta-d-Apif-(1-->2)-alpha-D-GalpA-OMe disaccharide.

Carbohydrate Conformation↗
PubMed2005

Synthesis of sterically crowded derivatives of anomeric pairs of D-glucose disaccharides.

Derivatization of carbohydrates is of considerable interest since the derivatives can be used for structural studies in the field of mass spectrometry. We report here the synthesis of a series of sterically crowded derivatives of various linkage and stereo-isomeric glucose-glucose disaccharides with the impetus being to understand the effect of these derivatized groups on fragmentation of the glycosidic bond and the development of methodology for discernment of the anomeric configuration. The synthesis of per-alkylated (methyl, ethyl, propyl, butyl, and pentyl), per-esterified (acetyl, pivaloyl, mesitoyl), and per-silylated (tert-butyl-dimethyl silyl) glucose--glucose disaccharide derivatives has been reported.

Acetylation↗
PubMed2006

Synthesis of n-octyl 2,6-dideoxy-alpha-L-lyxo-hexopyranosyl-(1-->2)-3-amino-3-deoxy-beta-D-galactopyranoside, an analog of the H-disaccharide antigen.

The synthesis of an analog of the H-disaccharide antigen (2), in which the galactopyranosyl moiety bears an amino group at C-3 and the fucopyranosyl residue is deoxygenated at C-2, is reported. The key reaction in the preparation of 2 was the glycosylation of an appropriately protected n-octyl 3-azido-3-deoxy-galactopyranoside derivative with a 2,6-dideoxy thioglycoside promoted by 1-(phenylsulfinyl)piperidine and triflic anhydride. Disaccharide 2 is of interest in studies directed towards understanding the molecular basis of substrate recognition by the blood group A and B glycosyltransferases.

Antigens, Bacterial↗