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PubMed1988

Synthesis of a trisaccharide of 3-deoxy-D-manno-2-octulopyranosylonic acid (KDO) residues related to the genus-specific lipopolysaccharide epitope of Chlamydia.

The disaccharides, O-(sodium 3-deoxy-alpha- and -beta-D-manno-2-octulopyranosylonate)-(2----8)-sodium (allyl 3-deoxy-alpha-D-manno-2-octulopyranosid)onate, were prepared via glycosylation of methyl (allyl 4,5,7-tri-O-acetyl-3-deoxy-alpha-D-manno-2-octulopyranosid)onat e with methyl (4,5,7,8-tetra-O-acetyl-3-deoxy-D-manno-2-octulopyranosyl bromide)onate under Helferich and Koenigs-Knorr conditions, respectively. Based on g.l.c.-m.s. data of the alpha- and beta-(2----8)-linked disaccharide derivatives, obtained after carbonyl- and carboxyl-group reduction, followed by methylation, the alpha-anomeric configuration was assigned to the terminal KDO-residue in the KDO-region of Chlamydial lipopolysaccharide. The trisaccharide O-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2----8)-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2----4)-sodium (allyl 3-deoxy-alpha-D-manno-2-octulopyranosid)onate was obtained via block synthesis using an alpha-(2----8)-linked disaccharide bromide derivative as the glycosyl donor. Copolymerization of the allyl glycosides with acrylamide gave water-soluble macromolecular antigens, suitable for defining epitope specificities of monoclonal antibodies directed against Chlamydial LPS.

Acrylamide↗
PubMed1988

Synthesis of a close analog of the repeating unit of the antifreeze glycoproteins of polar fish.

The protected glycopeptide N-(benzyloxycarbonyl)-L-alanyl-[O-(2,3,4,6-tetra-O-benzoyl-beta-D- galactopyranosyl)-(1----3)-O-(2,4,6-tri-O-benzyl-alpha-D-galactopyranosy l)- (1----3)]-L-threonyl-L-alanine 2,2,2-trichloroethyl ester was made by coupling the respective disaccharide and tripeptide blocks. The disaccharide block was generated by coupling tetra-O-benzoyl-alpha-D-galactopyranosyl bromide to allyl 2,4,6-tri-O-benzyl-alpha-D-galactopyranoside and converting the product into O-(2,3,4,6-tetra-O-benzoyl-beta-D-galactopyranosyl)-(1----3)-2,4,6-tri-O -benzyl - alpha-D-galactopyranosyl chloride via the 1-propenyl glycoside and the free (1-OH) sugar. Alternatively, the 1-propenyl intermediate was obtained directly by using 1-propenyl 2,4,6-tri-O-benzyl-alpha-D-galactopyranoside as the acceptor in the initial coupling reaction. An efficient 3-step synthesis of 10 was accomplished by the dibutyltin oxide-assisted, selective crotylation of allyl alpha-D-galactopyranoside at O-3, followed by benzylation and treatment of the product with potassium tert-butoxide. The N-benzyloxycarbonyl (Z) and N-tert-butoxycarbonyl (Boc) 2,2,2-trichloroethyl esters of Thr-Ala and Ala-Thr-Ala were formed by sequential coupling. The silver triflate-promoted glycosylation of the Z-protected dipeptide and tripeptide by 2,3,4,6-tetra-O-benzyl-alpha-D-galactopyranosyl chloride, and of the tripeptide by 6, proceeded with excellent alpha-stereoselectivity. From the disaccharide tripeptide 21, the carboxyl-deprotected and fully deprotected derivatives were prepared.

Animals↗
PubMed1994

Facile synthesis of the sugar cores from phenylpropanoid glycosides.

Allyl 2-O-benzoyl-4,6-O-benzylidene-alpha-D-glucopyranoside (3), obtained by selective benzoylation of allyl 4,6-O-benzylidene-alpha-D-glucopyranoside (2) with benzoyl chloride-imidazole in anhydrous chloroform, reacted with 2, 3, 4-tri-O-benzoyl-alpha-L-rhamnopyranosyl bromide to give a disaccharide derivative (4), and an important intermediate (5) was obtained by cleavage of its acetal. Treatment of 5 with a series of glycopyranosyl bromides, protected by acetyl or benzoyl groups in benzene-nitromethane in the presence of Hg(CN)2 as a catalyst afforded four trisaccharides (6-9). The disaccharide (5) and trisaccharides (6-9) constitute the sugar cores of phenylpropanoid glycosides. A new glycosyl anomeric leaving group, trichloroacetoxy, was employed to prepare the disaccharide (4) and trisaccharides residue (8) efficiently and with high stereoselectivity.

Carbohydrate Conformation↗
PubMed1994

Synthesis of carboxyl-reduced analogues related to the Chlamydia-specific Kdo trisaccharide epitope.

The disaccharides allyl O-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2-->4)-3-deoxy-a lph a-D- manno-2-octulopyranoside (8), allyl O-(3-deoxy-alpha-D-manno-2-octulopyranosyl)-(2-->8)-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosidonate) (24), and allyl O-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2-->8)-3-deoxy-a lph a-D- manno-2-octulopyranoside (35), and the trisaccharides allyl O-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2-->8)-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2-->4)-3-deoxy-a lph a-D-manno-2-octulopyranoside (13) and allyl O-(3-deoxy-alpha-D-manno-2-octulopyranosyl)-(2-->8)-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2-->4)-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosidonate) (30) were prepared. The ketosidic linkages were formed in good yields and high stereoselectivity by BF3 . Et2O-catalyzed reaction of the per-O-acetylated 3-deoxy-alpha-D-manno-2-octulopyranosyl fluoride derivative (16) with 8-O-SiButMe2 derivatives 19 and 21. Coupling reactions using the Kdo monosaccharide bromide derivative 4 or the alpha-(2-->8)-linked Kdo disaccharide bromide derivatives 9 and 26 were performed under Helferich conditions in MeCN or MeNO2, respectively. The disaccharide halides were prepared in good overall yields starting from the readily available allyl beta-glycoside of Kdo. The deprotected oligosaccharides correspond to the genus-specific lipopolysaccharide epitope of Chlamydia and part structures thereof, containing the carboxyl-reduced Kdo-residues at the distal and proximal position of the Kdo trisaccharide epitope, respectively.

Carbohydrate Conformation↗
PubMed1986

A characterization of the BALB/c lambda and kappa class antibodies to alpha (1,3) glycosidic linkages.

The avidity relationships of kappa and lambda antibodies with specificity for the glucosyl-alpha (1,3)-glucose disaccharide epitope were compared using a solid-phase hapten inhibition assay. The kappa class antibodies, induced by the T-cell-dependent antigen, nigerosyl-keyhole limpet hemocyanin (N-KLH), and the lambda class antibodies, induced by the T-cell-independent antigen, Dextran B1355, were only marginally distinguishable (approximately equal to 10-fold) on the basis of hapten inhibition using the free disaccharide, nigerose, as inhibitor. Analysis of the binding site sizes of antibodies induced by N-KLH through inhibition with oligosaccharides of different sizes showed that the disaccharide protein antigen did not select for antibodies with smaller binding site sizes. The cellular basis for these findings is discussed.

Animals↗
PubMed1982

Diagnosis of Sanfilippo type A syndrome by estimation of sulfamidase activity using a radiolabelled tetrasaccharide substrate.

1. A radiolabelled tetrasaccharide mixture (GlcNS-UA-GlcNS-UOA) containing GlcNSO3-UA-GlcNSO3-L-[6, 3H]idonic acid, GlcNSO3-UA-GlcNSO3-anhydro-L-[6, 3H]idonic acid and GlcNSO3-UA-GlcNSO3-L-[6, 3H]gulonic acid was evaluated together with a radiolabelled disaccharide O-(alpha-2-sulfamino-2-deoxy-D-glucopyranosyl)-(1 leads to 3)-L-[6, 3 H]idonic acid (GlcNS-IdOA) and a trisaccharide GlcNSO3-UA-D-[1, 3 H]glucosaminitol N-sulfate (GlcNS-UA-GlcitolNS) as diagnostic substrates for sulfamidase present in cultured human skin fibroblasts and leucocytes. 2. Sulfamidase activity assessed with GlcNS-UA-GlcNS-UOA was up to 10 times higher than the value obtained for GlcNS-IdOA and the trisaccharide. These results demonstrate that an adjacent GlcNS-UOA disaccharide residue to the sulfaminoglucosamine under attack may play a role in the mechanism of action or binding of sulfamidase toward its substrates. 3. Sulfamidase activity in fibroblast and leucocyte homogenates with GlcNS-UA-GlcNS-UOA exhibited a pH optimum at pH 5.0, an apparent Km of 27 to 50 mumol/l and inhibition by both NaCl and Na2SO4. 4. No detectable sulfamidase activity toward the tetrasaccharide, trisaccharide and disaccharide substrates could be detected using homogenates of fibroblast cultures from Sanfilippo A patients (sulfamidase deficient). Sulfamidase activity assayed with GlcNS-UA-GlcNS-UOA clearly distinguished Sanfilippo A patients from normal controls, heterozygotes and other mucopolysaccharidosis types. Because of the higher activity of sulfamidase toward the tetrasaccharide substrate, compared to that observed for the other substrates evaluated, we recommend its use for the routine enzymic detection of the Sanfilippo A syndrome.

Cell Line↗
PubMed1992

American Leishmania spp. and Trypanosoma cruzi: galactosyl alpha(1-3) galactose epitope localization by colloidal gold immunocytochemistry and lectin cytochemistry.

Patients with Chagas' disease or different clinical forms of leishmaniasis (cutaneous or visceral) have elevated galactosyl alpha (1-3)galactose antibodies. Using colloidal gold immunocytochemistry--monoclonal antibody gal-13 (specific for lipid-linked galactosyl alpha (1-3)galactose residues) and anti-nidogen antibodies and lectin cytochemistry (Bandeiraea simplicifolia IB4), both techniques specific for demonstrating galactosyl alpha (1-3)galactose residues--we have found terminal disaccharide residues on the Trypanosoma cruzi external surface of Vero cell-derived trypomastigotes but not in intact epimastigotes (although disrupted epimastigotes strongly stained), in the lips of the flagellar pocket, and on the parasitic side exactly opposite to the flagellar pocket in amastigote and promastigote forms of American Leishmania. These results resemble those obtained using anti-laminin antibodies in both trypanosomatids. In addition, results obtained with anti-nidogen antibodies seem to recognize in Trypanosoma cruzi and American Leishmania culture forms another different unknown terminal disaccharide. These results confirm the presence of terminal galactosyl alpha (1-3)galactose residues in both trypanosomatids, and that rabbit anti-laminin antibodies are indeed also recognizing galactosyl alpha (1-3)galactose residues as demonstrated for human circulating antibody. The presence of abundant galactosyl alpha (1-3)galactose residues on Trypanosomatid family members suggests a specific unknown role in parasite physiology for this terminal disaccharide.

Animals↗
PubMed1993

Characterization of the chemical structure of sulphated glycosaminoglycans after enzymatic digestion. Application of liquid chromatography-mass spectrometry with an atmospheric pressure interface.

Pneumatically assisted electrospray was demonstrated to be a powerful ionization source for the analysis of oligosaccharides. A mass spectrometer was interfaced to an HPLC system, using this interface, to determine oligosaccharides from the enzymatic digestion of heparin separated on a reversed-phase column. To set up the technique, and particularly to clarify the ionization process, purified disaccharides, from enzymatic digestion of chondroitin sulphates, were measured. The use of a suitable counter ion in the mobile phase, tetrapropylammonium (TPA), to optimize the HPLC separation, gave, with sulphated di- and oligosaccharides, adducts [M + nTPA - (n + m)H]m-, which were unexpectedly stable to fragmentation; molecular ions [M - (n + 1)H]n-, in the presence of the counter ion, were observed only with desulphated or monosulphated disaccharides. The stability of the adducts and the use of a deuterated ion-pair reagent permitted an exact evaluation of the molecular masses of disaccharides and oligosaccharides of unknown structure. Spectra obtained in the absence of the counter ion contained singly or multiply charged molecular ions and fragmentation ions mainly from loss of the sulphate groups; under these ionization conditions the exact mass determination and interpretation of the spectra were difficult. After removal of the counter ion, tandem mass spectra could be obtained with some interesting data for the characterization of these molecules. Complete spectral analyses were performed with amounts of samples of 50 micrograms but, using microbore columns, one twentieth of this amount may give good spectra.

Atmospheric Pressure↗
PubMed1996

Simple and sensitive multi-sugar-probe gut permeability test by high-performance liquid chromatography with fluorescence labelling.

Enteral intake of a mixture of inert, non-metabolic monosaccharide and disaccharide probes, followed by measurement of their urinary probe ratio, is a well known method to investigate gut permeability. However, most applications lack sensitivity, thus a large amount of especially the disaccharide lactulose has to be ingested. This may cause diarrhoea, which influences the outcome of the test. Recently, a new fluorescent label 9-fluorenylethyl chloroformate hydrazine (FMOC-hydrazine) was introduced, which reacts with reducing sugars to form stable and highly fluorescent single peak derivatives in organic medium. We applied this reagent to develop a sensitive measurement of reducing sugar probes in aqueous samples (e.g., urine). The presented method has a linear response for each sugar derivative between 1 and 1250 pmol with an R2 ranging from 0.9997 for lactulose to 0.9999 for rhamnose. The limit of detection, calculated as a signal-to-noise ratio of three, was 0.05 pmol for lactulose and 0.01 pmol for rhamnose, xylose and 3-O-methyl-D-glucose, corresponding to urine concentrations of 0.11 micromol/l for lactulose and 0.02 micromol/l for rhamnose, xylose and 3-O-methyl-D-glucose. Compared to other tests, the limit of detection is very low. This enabled a reduction in the enteral intake of the disaccharide lactulose from 6-10 g to 1.5 g, thereby minimizing the chance of introducing diarrhoea. The coefficient of variation was below 3% both in standards and urine samples. After spiking the urine with the saccharides a recovery of 102% for lactulose, 101% for rhamnose, xylose and 3-O-methyl-D-glucose was found. In order to evaluate the presented method we compared the lactulose rhamnose ratio measured in urine of healthy human volunteers and kept the ingested dose in agreement with literature values. Furthermore, the ratio was measured after 3, 6 and 9 h to establish the minimal response time required to measure correct ratios. We found that even after 3 h the ratio was stable at a value of 0.0133 which is comparable to literature values (0.008-0.052).

3-O-Methylglucose↗
PubMed1984

Evidence for diabetes-induced alterations in the sulfation of heparin sulfate intestinal epithelial cells.

35S-heparan sulfate (HS) metabolism by intestinal epithelial cells isolated from streptozotocin-diabetic and control rats was studied. In diabetic cells, a greater amount of 35S-radioactivity was incorporated into HS, however specific radioactivity of this polysaccharide was decreased. Studies into the distribution of sulfate residues in HS after selective deamination of the glucosamine units within the glycosaminoglycan (GAG)-chain, demonstrated that O-sulfate groups are preferentially located in relatively small deamination products: tetrasaccharides and disaccharides. A lower amount of radioactivity related to N-sulfate groups was found in HS from diabetic cells compared to that of control cells demonstrating that, in diabetes, less glucosamine residues within HS chains are subjected to N-sulfation. An increase in the percentage of 35-sulfate and in the percentage amount of uronic acid in tetrasaccharides of HS of diabetic cells indicated that a greater number of tetrasaccharides were generated by deaminative degradation of this HS. Since a decrease in the specific activity of uronic acid in disaccharides as in tetrasaccharides from HS of diabetic cells was observed, it is clear that the degree of O-sulfation of this HS is reduced. It is suggested, that "in vivo" changes in HS metabolism in diabetic intestinal epithelial cells lie in a disturbance in the degree of N- and O-sulfation of disaccharide units within the HS macromolecule.

Animals↗
PubMed1994

Determination of the HNK-1 epitope (3-sulphated glucuronic acid) in intact chondroitin sulphates by ELISA. Application to squid skin proteoglycans and their oversulphated carbohydrate structures.

The reactivity of the HNK-1 monoclonal antibody to chondroitin sulphates and derived disaccharides was studied using an ELISA inhibition test. The antibody readily reacted with its specific epitope (3-sulphated glucuronic acid) in intact chondroitin sulphates as well as with the equivalent oversulphated delta 4-disaccharides obtained by chondroitinase digestion and identified as sulphated at C-3 of the hexuronate. It is showed that by using the oversulphated delta 4-disaccharides as standards in an ELISA inhibition test, the amount of 3-sulphated glucuronic acid can be estimated also in the polymer preparations. When applying this ELISA test to the PG populations isolated from squid skin, most of the oversulphation seen in HPLC analyses of these preparations was found to be associated with 3-sulphation of the glucuronic acid.

Animals↗
PubMed1981

Effect of dibutyryl cyclic AMP on the sulphation of proteoglycans by chondrocytes.

The addition of a 1 mM N6, O2'-dibutyryl cyclic AMP to incubations of foetal calf articular cartilage for a 4 h period resulted in a 13 and a 15% decrease, respectively, in the rate of incorporation of [3H]glucosamine and [14C]glucose into glycosaminoglycans. Under the same conditions, a 41% increase in the rate of incorporation of [35S]sulphate into glycosaminoglycans was observed. Dibutyryl cyclic AMP had no effect on protein synthesis over a 4 h period or on the hydrodynamic size of the proteoglycan subunits or glycosaminoglycans synthesized by the cartilage. When the glycosaminoglycans were digested with chondroitin ABC lyase and the resulting disaccharides analysed on Dowex 1 (formate form), it was observed that dibutyryl cyclic AMP increased the degree of sulphation of the disaccharides. Furthermore, an over-sulphated disaccharide corresponding to chondroitin 4,6-disulphate was identified. It was concluded that dibutyryl cyclic AMP was stimulating the process of sulphation of glycosaminoglycans by cartilage.

Animals↗
PubMed2006

Diversity in the degree of sulfation and chain length of the glycosaminoglycan moiety of urinary trypsin inhibitor isomers.

Five isomers with different electric charge were fractionated from human urinary trypsin inhibitor (UTI) by anion exchange HPLC. Intact low-sulfated chondroitin 4-sulfate chains from the isomers were analyzed by HPLC and mass spectrometry. Unsaturated disaccharide composition analysis of the chondroitin sulfate chain revealed that the five isomers differ in the numbers of 4-sulfated disaccharide units. Intriguingly, we detected the presence of multiple novel isomers with different numbers of non-sulfated disaccharide units even in the same charge isomer fraction. Our results demonstrate that UTI can vary in terms of both the degree of sulfation and the length of the low-sulfated chondroitin 4-sulfate chain.

Carbohydrate Sequence↗
PubMed2005

NAD+ and metal-ion dependent hydrolysis by family 4 glycosidases: structural insight into specificity for phospho-beta-D-glucosides.

The import of disaccharides by many bacteria is achieved through their simultaneous translocation and phosphorylation by the phosphoenolpyruvate-dependent phosphotransferase system (PEP-PTS). The imported phospho-disaccharides are, in some cases, subsequently hydrolyzed by members of the unusual glycoside hydrolase family GH4. The GH4 enzymes, occasionally found also in bacteria such as Thermotoga maritima that do not utilise a PEP-PTS system, require both NAD(+) and Mn(2+) for catalysis. A further curiosity of this family is that closely related enzymes may show specificity for either alpha-d- or beta-d-glycosides. Here, we present, for the first time, the three-dimensional structure (using single-wavelength anomalous dispersion methods, harnessing extensive non-crystallographic symmetry) of the 6-phospho-beta-glycosidase, BglT, from T.maritima in native and complexed (NAD(+) and Glc6P) forms. Comparison of the active-center structure with that of the 6-phospho-alpha-glucosidase GlvA from Bacillus subtilis reveals a striking degree of structural similarity that, in light of previous kinetic isotope effect data, allows the postulation of a common reaction mechanism for both alpha and beta-glycosidases. Given that the "chemistry" occurs primarily on the glycone sugar and features no nucleophilic attack on the intact disaccharide substrate, modulation of anomeric specificity for alpha and beta-linkages is accommodated through comparatively minor structural changes.

Bacterial Proteins↗
PubMed2005

Wild blueberry (Vaccinium angustifolium) consumption affects the composition and structure of glycosaminoglycans in Sprague-Dawley rat aorta.

It has been documented that increased intake of polyphenols may provide protection against coronary heart disease and stroke. Blueberries (Vaccinium angustifolium) are one of the richest sources of antioxidants among fruits and vegetables. Phenolic compounds from berry extracts inhibit human low density lipoprotein and liposome oxidation. Glycosaminoglycans (GAGs) and proteoglycans (PGs) are structural components of aortas with great structural diversity. Their interaction with compounds such as enzymes, cytokines, growth factors, proteins and lipoproteins and their subsequent role in degenerative diseases has been documented. We investigated the effects of a diet rich in blueberries on the content and structure of GAGs. Sprague-Dawley rats were fed either a control (C) or a blueberry (B) diet for 13 weeks. Aortic tissue GAGs were isolated with papain digestion, alkaline borohydride treatment and anion-exchange chromatography. Cellulose acetate electrophoresis and treatment of the fractions with specific lyases revealed the presence of three GAG populations, i.e. hyaluronan (HA), heparan sulfate (HS) and galactosaminoglycans (GalAGs). Disaccharide composition was determined by high-performance capillary electrophoresis following enzymatic degradation. A 13% higher amount of total GAGs in aortas of B-fed rats was attributed to a higher content of GalAGs (67%). Determination of the sulfated disaccharides showed an overall lower concentration of oversulfated disaccharides in both HS and GalAG populations in the aortas of the B group. Our results demonstrate for the first time that a diet rich in blueberries results in structural alterations in rat aortic tissue GAGs. These changes may affect cellular signal transduction pathways and could have major consequences for the biological function of GAG molecules within the vascular environment.

Animals↗
PubMed2002

Microanalysis of hyaluronan oligosaccharides by polyacrylamide gel electrophoresis and its application to assay of hyaluronidase activity.

We established a rapid, sensitive polyacrylamide gel electrophoresis (PAGE) method for the analysis of hyaluronan (HA) oligosaccharides. Using mini-slab gels, but not large-slab gels so far reported, HA oligosaccharides of 5 to more than 50 repeating disaccharide units could be separated into discrete ladder-like bands in a short electrophoresis time of 45 min. Using a combined Alcian blue and silver staining protocol, the detection limit was less than 1 ng per band for 11 repeating disaccharide units, indicating 50 times higher sensitivity than that of an earlier-described sensitivity-enhanced PAGE method. Our PAGE method was applicable to the assay of hyaluronidase activity. When a total of multiple band intensities for 18-24 repeating disaccharide units was used as a measure of activity, as little as 3 x 10(-4) NFU of bovine testicular hyaluronidase was detectable on a 1-h incubation. This sensitivity permitted rapid measurements of human and rabbit serum hyaluronidases, the latter of which having never been detected even by a sensitive enzyme-linked immunosorbent assay (ELISA). Since this PAGE assay does not require specialized reagents and instruments and since it provides information on both the activity and the enzymatic HA degradation pattern, there may be many potential applications.

Animals↗
PubMed2000

c,T-dependence of the viscosity and the self-diffusion coefficients in some aqueous carbohydrate solutions.

Self-diffusion coefficients for both components are reported for the highly concentrated aqueous solutions of some disaccharides and fructose as a function of temperature and concentration. These data are complemented by viscosity measurements. The disaccharides studied are sucrose, alpha,alpha-trehalose, allosucrose, and leucrose. Up to a sugar concentration of approximately 30% w/w the viscosity and the self diffusion coefficients of the four disaccharides are identical within experimental error for a given concentration and temperature. Water diffusion shows no differences in the four systems studied under these conditions. At higher concentrations significant differences are observed that become more pronounced with increasing temperature. Analysis of the data by the VTF equation yields the result that at a given concentration the self diffusion coefficients of the sugar Dc and the viscosity eta are described by identical ideal glass transition temperatures T0, while the diffusion of the water D(W) molecule decouples from these properties. T0(W) is always lower than T0(c,eta).

Carbohydrates↗
PubMed1975

[Synthesis of 2-acetamido-2-deoxy-6-0-(alpha-D-glucopyranosyl)-alpha-D-galactopyranose and its p-aminophenyl-alpha-glycoside].

Benzyl 2-acetamido-3, 4-di-O-acetyl-2-deoxy-alpha-D-galactopyranoside was condensed with 2, 3, 4-tri-O-benzyl-6-O-p-nitrobenzoyl-alpha-D-glucopyranosyl bromide or with 2, 3, 4-tri-O-benzyl-6-O-p-methoxybenzoyl-alpha-D-glucopyranosyl bromide in benzene at 50 degrees in the presence of pyridine, to give benzyl 2-acetamido-3, 4-di-O-acetyl-2-deoxy-6-O-[2, 3, 4-tri-O-benzyl-6-O-p-nitro(or methoxy)benzoyl]-alpha-D galactopyranoside in excellent yield. The title disaccharide was obtained in crystalline form after deacylation and catalytic hydrogenation. It proved identical with a disaccharide isolated from Salmonella johannesburg 5.58 (40) converted by phage phi 1 (40). In order to bind this disaccharide covalently onto various proteins, p-aminophenyl 2-acetamido-2-deoxy-6-O-(alpha-D-glucopyranosyl)-alpha-D-galactopyranoside has been obtained in an analogous way, starting from p-nitrophenyl 2-acetamido-3, 4-di-O-acetyl-2-deoxy-alpha-D-galactopyranoside.

Binding Sites↗