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PubMed1975

Structure of heparin. Characterization of the products formed from heparin by the action of a heparinase and a heparitinase from Flavobacterium heparinum.

The total degradation of heparin by the joint action of a purified heparinase and a heparitinase from Flavobacterium heparinum is reported. The heparinase acts directly upon heparin, yielding 52% of a trisulfated disaccharide (O-(alpha-L-ido-4-enepyranosyluronic acid 2-sulfate)-(1leads to 4)-2sulfoamino-2-deoxy-D-glucose 6-sulfate) and 40% of a tetrasaccharide besides small amounts of hexa- and disaccharides. The tetrasaccharide is in turn completely degraded by the heparitinase, forming trisulfated disaccharide and disulfated disaccharide (O-(alpha-D-glyco-4-enepyranosyluronic acid)-(1leads to 4)-2-sulfoamino-2-deoxy-D-glucose 6-sulfate) in equal amounts. These and other results indicate that the tri- and disulfated disaccharides are linked alternately, in a proportion of 3:1, respectively. The primary structure of heparin and the mode of action of the heparinase and the heparitinase are proposed based on the analysis of the different products formed by the action of the enzymes.

Flavobacterium↗
PubMed1992

The antiproliferative activity of arterial heparan sulfate resides in domains enriched with 2-O-sulfated uronic acid residues.

Heparan sulfate isolated from bovine arterial tissue by a multistep purification procedure or from arterial tissue proteoheparan sulfate by beta-elimination exhibits antiproliferative activity toward arterial smooth muscle cells when added to subconfluent cell cultures in a concentration of 50-100 micrograms/ml medium. Enzymatic disintegration of heparan sulfate by heparitinases I and II and isolation of the resulting oligosaccharides indicate that the antiproliferative activity of the heparan sulfate molecule resides in a sulfate-rich octa/decasaccharide domain which is separated by longer sequences of sulfate-free or sulfate-poor N-acetylglucosamine containing disaccharide units. The octa/decasaccharide fraction has a 3-4-fold higher antiproliferative activity than the native heparan sulfate molecule and contains 45% of a disulfated disaccharide which consists of 2-O-sulfated uronic acid and N-sulfated glucosamine (UA(2S)-GlcNS and 12% of a trisulfated disaccharide (UA(2S)-GlcNS(6S). A sulfate-rich hexasaccharide fraction containing 14% of the disulfated disaccharide but 18% of the trisulfated disaccharide has negligible antiproliferative activity. The results indicate the presence of specific structural determinants in the arterial heparan sulfate molecule which may have the function of an endogenous inhibitor of arterial smooth muscle cell growth.

Animals↗
PubMed1986

Use of synthetic glycoconjugates containing the Mycobacterium leprae specific and immunodominant epitope of phenolic glycolipid I in the serology of leprosy.

The high specificity of phenolic glycolipid I (PG-I) in the identifying individuals with leprosy appears to be attributable to the species-specific trisaccharide region of the molecule. Synthetic glycoconjugates were produced by coupling the corresponding terminal mono- or disaccharide to bovine serum albumin by reductive amination. Conjugates which contained only the terminal sugar maintained in its pyranose form, the terminal disaccharide with only the terminal sugar in its pyranose form and the terminal disaccharide with both the 3,6,di-o-Me-glucose and 2,3,di-o-Me-rhamnose sugars in their pyranose forms, were all highly active in the enzyme-linked immunosorbent assay (ELISA) and showed good concordance with native PG-1 in analysis of sera from leprosy patients. The antibody levels to the glycoconjugates in tuberculosis patients and patients with other mycobacterial infections were not significantly different from the levels in normal healthy control subjects. A few of the leprosy sera showed much stronger binding to conjugates which contained the disaccharide with both sugars in the pyranose form than to conjugates with only the terminal sugar in its pyranose form. Therefore a synthetic conjugate which contains the intact disaccharide region of PG-I may provide the most sensitive antigen for the large scale serodiagnosis of leprosy.

Antibodies, Bacterial↗
PubMed1989

Resistance of heparinase-derived heparin fragments to biotransformation.

The biotransformation of heparinase-derived heparin fragments was examined via a combined approach using 35S-labeled heparin fragments as well as unlabeled chemically defined heparin fragments. Rats dosed with either [35S]di-, tetra-, hexa-, or octasaccharide fragments (2 mg/kg body weight, intravenously) excreted 63-69% of the injected radioactivity into the urine within 24 h with two-thirds being excreted during the first 6 h. Gel permeation chromatography of the urinary material shows that the tetra- and octasaccharides have undergone minor (approximately 5%) depolymerization whereas no change was observed for the di- and hexasaccharides. No N-desulfation was demonstrated for any of the substances. The hexa- and octasaccharide metabolites present in the urine 24 h after dosing exhibited the same antifactor Xa activity as that of the injected material. A chemically defined trisulfated disaccharide and a hexasulfated tetrasaccharide were prepared and dosed in a similar manner. Only one metabolite was recovered from animals dosed with disaccharide. This compound was characterized by anion exchange chromatography, proton nuclear magnetic resonance spectroscopy, Fourier transform infrared spectrometry, and mass spectrometry and shown to be identical to the injected disaccharide. Five metabolites were isolated from the urine of rats dosed with the hexasulfated tetrasaccharide. The major metabolite, consisting of at least 65% of the total, was characterized as described for the disaccharide and shown to be identical to the injected compound. The remaining material appeared to be disaccharides and, possibly, a tetrasaccharide conjugate. Taken together, our results show that the heparinase-derived heparin fragments are very resistant to biotransformation compared with heparin and endogenous heparin fragments. These fragments may therefore be useful in defining structure activity relationships in vivo.

Animals↗
PubMed1986

Formation of dermatan sulfate by cultured human skin fibroblasts. Effects of sulfate concentration on proportions of dermatan/chondroitin.

[3H,35S]Dermatan/chondroitin sulfate glycosaminoglycans produced during culture of fibroblasts in medium containing varying concentrations of sulfate were tested for their susceptibility to chondroitin ABC lyase and chondroitin AC lyase. Chondroitin ABC lyase completely degraded [3H]hexosamine-labeled and [35S] sulfate-labeled dermatan/chondroitin sulfate to disaccharides. Chondroitin AC lyase treatment of the labeled glycosaminoglycans produced different results. With this enzyme, dermatan/chondroitin sulfate formed at high concentrations of sulfate yielded small glycosaminoglycans and larger oligosaccharides but almost no disaccharide. This indicated that the dermatan/chondroitin sulfate co-polymer contained mostly iduronic acid with only an occasional glucuronic acid. As the medium sulfate concentration was progressively lowered, there was a concomitant increase in the susceptibility to degradation by chondroitin AC lyase. Thus, the labeled glycosaminoglycans formed at the lowest concentration of sulfate yielded small oligosaccharides including substantial amounts of disaccharide. The smaller chondroitin AC lyase-resistant [3H,35S]dermatan/chondroitin sulfate oligosaccharides were analyzed by gel filtration. Results indicated that, in general, the iduronic acid-containing disaccharide residues present in the undersulfated [3H,35S]glycosaminoglycan were sulfated, whereas the glucuronic acid-containing disaccharide residues were non-sulfated. This work confirms earlier reports that there is a relationship between epimerization and sulfation. Moreover, it demonstrates that medium sulfate concentration is critical in determining the proportions of dermatan to chondroitin (iduronic/glucuronic acid) produced by cultured cells.

Adult↗
PubMed1984

Antibody to epiglycanin and radioimmunoassay to detect epiglycanin-related glycoproteins in body fluids of cancer patients.

By means of a radioimmunoassay, which utilized [125I]-epiglycanin and anti-epiglycanin antiserum induced in rabbits by injections of viable TA3-Ha ascites cells with Freund's complete adjuvant, picogram quantities of epiglycanin could be detected. Anti-epiglycanin antiserum was similarly produced in allogeneic mice. Unlabeled epiglycanin lost the capacity to compete with [125I]epiglycanin in the radioimmunoassay as a result of periodate oxidation or incubation with endo-alpha-N-acetyl-D-galactosaminidase (Diplococcus pneumoniae), an enzyme found to cleave only the disaccharide beta-D-galactopyranosyl-(1----3)-2-acetamido-2-deoxy-D-galactose chain from serine or threonine residues in epiglycanin. Glycosylhydrolases known to cleave alpha-D-mannose, beta-D-galactose (1,4-linked), beta-N-acetyl-D-glucosamine, and alpha-N-acetyl-D-galactosamine did not reduce the activity of epiglycanin. Neuraminidase enhanced the activity twofold to fivefold. The finding that little or no activity was demonstrated by the disaccharide, the reduced disaccharide, or other glycoproteins containing the same disaccharide chain suggested that the antigenic determinant probably involved the disaccharide and a unique amino acid sequence at the site of its attachment. By means of the radioimmunoassay epiglycanin cross-reactive antigens were detected in the peritoneal or pleural fluid and in the sera of patients with metastatic cancer. Lower concentrations of epiglycanin-like antigen(s) were found in the peritoneal fluid of patients with hepatitis or liver cirrhosis but not in normal serum.

Antibodies↗
PubMed1982

Biosynthesis of galactosyl-beta 1,3-N-acetylglucosamine.

The biosynthesis of galactosyl-beta 1,3-N-acetylglucosamine has been demonstrated using membrane preparations from pig trachea. Unlike the UDP-galactose:2-acetamido-2-deoxy-D-glucose 4 beta-galactosyltransferase, which is inhibited by high levels of N-acetylglucosamine, the UDP-galactose:N-acetylglucosamine 3 beta-galactosyltransferase shows no inhibition at 200 mM N-acetylglucosamine. About 80% of the total disaccharide synthesized at 200 mM N-acetylglucosamine was base-labile suggesting the 1,3-linkage, alpha-Lactalbumin inhibits galactose incorporation into galactosyl-beta 1,4-N-acetylglucosamine but has little or no effect on the activity of the 1,3-galactosyltransferase. Escherichia coli beta-galactosidase readily hydrolyzed the base-stable product, but not the base-labile component. The apparent 1,3-linked disaccharide was reduced with NaBH4 and was isolated by Bio-Gel P-2 column chromatography. Methylation analysis by gas chromatography/mass spectrometry showed tetramethyl galactose and a 3-substituted N-acetylglucosaminitol. Neither the beta 1,4 nor the beta 1,3 disaccharide was hydrolyzed by green coffee bean alpha-galactosidase. Both disaccharides were readily hydrolyzed by bovine testes beta-galactosidase. This is the first report on the galactosyltransferase which catalyzes the synthesis of the galactosyl-beta 1,3-N-acetylglucosamine linkage such as found in the Type I chain of human blood group substances. A tissue survey in rats showed only rat intestine to have readily detectable UDP-galactose: N-acetylglucosamine 3 beta-galactosyltransferase activity. The intestinal membrane fraction like the tracheal enzyme catalyzes the synthesis of two disaccharides as judged by base treatment, and these appear to be the beta 1,3 and beta 1,4 isomers of galactosyl-N-acetylglucosamine.

Acetylglucosamine↗
PubMed1995

Inhibition of the pig to human xenograft reaction, using soluble Gal alpha 1-3Gal and Gal alpha 1-3Gal beta 1-4GlcNAc.

Natural anti-carbohydrate antibodies are central to hyperacute rejection in ABO-incompatible allotransplantation and in discordant xenotransplantation. ABO-incompatible rejection has been inhibited successfully using intravenous soluble carbohydrates as antibody inhibitors. The approach has been less successful previously in pig to primate xenotransplantation, where the necessary concentrations of a partial inhibitor (Gal alpha 1-6Glc) proved highly toxic. In this study, we have identified more effective inhibitors of the dominant human anti-pig antibodies that bind to the pentasaccharide Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc beta 1-. The inhibitors are the terminal disaccharide (Gal alpha 1-3Gal) and terminal trisaccharide (Gal alpha 1-3Gal beta 1-4GlcNAc) of the target pentasaccharide. Twelve sera (3 from each ABO blood group) were tested in 3 different assays: lymphocytotoxic, lymphocyte flow cytometry, and solid-phase antigen ELISA. Fifty percent to 75% inhibition of human IgG and IgM was achieved using the disaccharide and trisaccharide inhibitors in the range of 10-50 mM. Disaccharide (70 mM) was used to inhibit hyperacute thrombosis in pig kidneys perfused for 40 min with heparinized human AB whole blood. The disaccharide completely inhibited red cell occlusion of glomerular but not of intertubular capillaries, although there was residual platelet thrombus in glomeruli. Disaccharide and trisaccharide can, therefore, be used in concentrations shown for other carbohydrate inhibitors to be nontoxic, for inhibition of hyperacute pig-to-human xenograft rejection. The inhibition is incomplete, however, and other antigen specificities and other rejection mechanisms are likely to be involved.

ABO Blood-Group System↗
PubMed1996

Physico-chemical properties and the structure of dermatan sulfate fractions purified from plasma after oral administration in healthy human volunteers.

Dermatan sulfate (DS) was administered by oral route in healthy human volunteers. The structure, physico-chemical properties and biological activity of DS purified from human plasma after oral administration were studied and compared with those of native DS. DS extracted and purified from pig mucosa has a relative molecular mass (Mr) of about 23,100 and is composed of about 10% nonsulfated disaccharide, 80% monosulfated disaccharides and about 10% disulfated disaccharides, with a sulfate to carboxyl ratio of 1.00 and a heparin cofactor II (HCII) activity of about 160 units/mg. This native polysaccharide is composed of about 94% iduronic acid. One gram of native DS was orally administered to five healthy human volunteers, and 50 ml of blood were collected after 4 h. DS possibly present in plasma after oral administration was extracted and purified. About 130 +/- 42 micrograms of DS per 50 ml of blood were detected by agarose-gel electrophoresis and DMB assay. This DS shows a broad Mr range. After oral absorption, substantial amounts of species with a Mr of about 7,500 are detected in blood but chains with Mr ranging from 7,500 to 20,000 are also found. Moreover, some very low-Mr species are detected, with a prevalence of disaccharides. After oral absorption, DS is sulfated above all in position 4 of the N-acetyl-galactosamine (60%), with a sulfate to carboxyl ratio of about 0.64, demonstrating that DS is desulfated during or after oral absorption by about 30-40%, A small amount of disulfated disaccharide (in particular 2,4-disulfated, 1.4%) is preserved from catabolic processes, as DS extracted from human plasma is able to inhibit thrombin activity mediated by HCII (about 16 U/mg).

Adult↗
PubMed1965

THE ISOLATION OF OLIGOSACCHARIDES FROM THE CELL-WALL POLYSACCHARIDE OF LACTOBACILLUS CASEI, SEROLOGICAL GROUP C.

1. A number of disaccharides and oligosaccharides have been isolated from the products of mild acid hydrolysis of the specific substance from Lactobacillus casei, serological group C. 2. The major disaccharide is O-beta-d-glucopyranosyl-(1-->3)-N-acetyl- d-galactosamine (B4) and evidence is presented for the structure of a tetrasaccharide composed of O-beta-d-glucopyranosyl-(1-->6)-d-galactose (B1) joined through its reducing end group to B4. 3. Disaccharide B1 is also a component of a trisaccharide O-beta-d-glucopyranosyl-(1-->6)-O-beta- d-galactopyranosyl-(1-->6)-N-acetyl-d-glucosamine (A7). 4. A number of other oligosaccharides have been shown to be related structurally. 5. The ability of certain of the oligosaccharides to inhibit the precipitin reaction has been studied. The disaccharide B1 is more effective as an inhibitor than gentiobiose and the trisaccharide A7 is considerably more effective than B1. 6. These results have been compared with those obtained previously for the composition of the cell wall.

Acetylglucosamine↗
PubMed1996

Experimental chiroptical verification of linkage flexibility in methyl 3-O-(alpha-d-mannopyranosyl)-alpha-d-mannopyranoside.

Vacuum UV CD spectra of methyl 3-O-(alpha-D-mannopyranosyl)-alpha-D- mannopyranoside in D2O and as a cast film were obtained in the 145-200 nM region. The disaccharide solution CD per residue is nearly identical to that of the monosaccharide solution CD, and to the monosaccharide film CD. Conversely, the disaccharide film spectrum exhibits a strong positive CD linkage contribution in the 160-170 nm range, which is consistent with the known crystal conformation under the aegis of previously determined sector rules. The close similarity between the monosaccharide and disaccharide solution spectra, therefore, reflects conformational averaging in which the net linkage contribution is approximately zero. The present observation of significant solution linkage flexibility confirms previous conclusions based on optical rotation, as well as conclusions of others based on nmr data. Moreover, when combined with those earlier results, the present work demonstrates the population of at least three distinct potential energy wells on the disaccharide phi,psi potential energy surface.

Carbohydrate Conformation↗
PubMed2001

Identification of oligomeric domains within dermatan sulfate chains using differential enzymic treatments, derivatization with 2-aminoacridone and capillary electrophoresis.

Galactosaminoglycans, i.e. dermatan sulfate (DS) and chondroitin sulfate, are linear heteropolysaccharides consisting of repeating disaccharide units of L-iduronic acid (L-IdoA) or D-glucuronic acid (D-GlcA) residues linked to N-acetyl-galactosamine. High-performance capillary electrophoresis (HPCE or CE) has been successfully used for determining the disaccharide composition of glycosaminoglycans. However, only limited information is available on how to identify oligomeric domains rich in D-GlcA or L-IdoA. The aim of this study was therefore to develop a rapid and accurate CE procedure by which such oligosaccharides can be determined together with the variously sulfated disaccharides. Isolated dermatan sulfates of human origin were separately digested with chondroitinases ABC, AC and B and the enzymic products were derivatized with 2-aminoacridone. CE analysis of these products was performed using a phosphate buffer, pH 3.0, and reversed polarity at 30 kV. The derivatization enabled their detection with laser-induced fluorescence (LIF) and UV at 260 nm at much higher sensitivity than the detection of nonderivatized delta-saccharides at 232 nm and therefore components undetectable at 232 nm were nicely detected after derivatization. Except for delta-disaccharides, altogether five distinct oligosaccharides with differences in charge density were identified. Depending on the lyase that produced these oligomers, information on the presence of L-IdoA- or D-GlcA-containing domains within the DS chain and the sulfation pattern of these oligomeric domains was obtained. This CE method could also be useful in studying the functional oligomeric domains in galactosaminoglycan chains.

Aminoacridines↗
PubMed2002

Molecular dynamics simulations of alpha2 --> 8-linked disialoside: conformational analysis and implications for binding to proteins.

Computational methods have played a key role in elucidating the various three-dimensional structures of oligosaccharides. Such structural information, together with other experimental data, leads to a better understanding of the role of oligosaccharide in various biological processes. The disialoside Neu5Ac-alpha2-->8-Neu5Ac appears as the terminal glycan in glycoproteins and glycolipids, and is known to play an important role in various events of cellular communication. Neurotoxins such as botulinum and tetanus require Neu5Ac-alpha2 --> 8-Neu5Ac for infecting the host. Glycoconjugates containing this disialoside and the enzymes catalyzing their biosynthesis are also regulated during cell growth, development, and differentiation. Unlike other biologically relevant disaccharides that have only two linkage bonds, the alpha2-->8-linked disialoside has four: C2-O, O-C8', C8'-C7', and C7'-C6'. The present report describes the results from nine 1 ns MD simulations of alpha2-->8-linked disialoside (Neu5Ac-alpha2-->8-Neu5Ac); simulations were run using GROMOS96 by explicitly considering the solvent molecules. Conformations around the O-C8' bond are restricted to the +sc/+ap regions due to stereochemical reasons. In contrast, conformations around the C2-O and C8'-C7' bonds were found to be largely unrestricted and all the three staggered regions are accessible. The conformations around the C7'-C6' bond were found to be in either the -sc or the anti region. These results are in excellent agreement with the available NMR and potential energy calculation studies. Overall, the disaccharide is flexible and adopts mainly two ensembles of conformations differing in the conformation around the C7'-C6' bond. The flexibility associated with this disaccharide allows for better optimization of intermolecular contacts while binding to proteins and this may partially compensate for the loss of conformational entropy that may be incurred due to disaccharide's flexibility.

Algorithms↗
PubMed2003

Modular synthesis of heparin oligosaccharides.

A general, modular strategy for the first completely stereoselective synthesis of defined heparin oligosaccharides is described. Six monosaccharide building blocks (four differentially protected glucosamines, one glucuronic and one iduronic acid) were utilized to prepare di- and trisaccharide modules in a fully selective fashion. Installation of the alpha-glucosamine linkage was controlled by placing a conformational constraint on the uronic acid glycosyl acceptors thereby establishing a new concept for stereochemical control. Combination of disaccharide modules to form trans-uronic acid linkages was completely selective by virtue of C2 participating groups. Coupling reactions between disaccharide modules exhibited sequence dependence. While the union of many glucosamine uronic acid disaccharide modules did not meet any problems, certain sequences proved not accessible. Elaboration of glucosamine uronic acid disaccharide building blocks to trisaccharide modules by addition of either one additional glucosamine or uronic acid allowed for stereoselective access to oligosaccharides as demonstrated on the example of a hexasaccharide resembling the ATIII-binding sequence. Final deprotection and sulfation yielded the fully synthetic heparin oligosaccharides.

Antithrombin III↗
PubMed2005

Separation, identification, and interaction of heparin oligosaccharides with granulocyte-colony stimulating factor using capillary electrophoresis and mass spectrometry.

A capillary electrophoresis (CE) method was developed for the separation of heparin oligosaccharides compatible to study the interactions between the oligosaccharides and granulocyte-colony stimulating factor (G-CSF). Unfractionated heparin was eliminitively degraded to heparin oligosaccharides by an endolytic heparinase. The degraded smaller oligosaccharides (M(r) < 1000) were baseline-separated by CE under a 50 mM phosphate buffer (pH 9.0) in 10 min. Standard heparin disaccharides and larger oligosaccharides (1000 < M(r) < 8000) were all separated under optimized separation conditions. Compared with standard heparin disaccharides, smaller oligosaccharides contained one nonsulfated, two monosulfated, and two disulfated disaccharides, but trisulfated disaccharides were not found. The smaller oligosaccharides were also identified and molecular mass was deduced by electrospray ionization-mass spectrometry (ESI-MS). Furthermore, interactions between G-CSF and the oligosaccharides were studied by using capillary zone electrophoresis (CZE) under the above separation conditions. It was found that larger oligosaccharides could interact with G-CSF while smaller oligosaccharides were not observed to bind to G-CSF under the experimental conditions. In conclusion, the purified heparinase could selectively degrade heparin into oligosaccharides and the interaction between G-CSF and heparin was correlated with the chain length of heparin.

Chromatography, Gel↗
PubMed2000

Separation of Galfbeta1-->XGlcNAc and Galpbeta1-->XGlcNAc (X = 3, 4, and 6) as the alditols by high-pH anion-exchange chromatography and thin-layer chromatography: characterization of mucins from Trypanosoma cruzi.

The O-linked N-acetylglucosamine oligosaccharides in the mucins of Trypanosoma cruzi may contain galactofuranose or galactopyranose, depending on the strain, one of the components being the disaccharide. Since galactofuranose is a site for antibody recognition, it is desirable to have a sensitive method for the detection of the galactofuranosyl structures. In this paper, we present procedures for the separation of Galfbeta1-->XGlcNAc and Galpbeta1-->XGlcNAc (X = 3, 4, and 6) as the corresponding alditols by high-pH anion-exchange chromatography with pulse amperometric detection. All the isomeric disaccharides could be resolved on a CarboPac PA-10 column, the galactofuranose-containing disaccharides being more retained in the column. GlcNAcol and Galfbeta1-->4(Galpbeta1-->6)GlcNAcol could be analyzed in the same run. The compounds could also be separated by thin-layer chromatography on silica gel 60, a convenient method for analysis of the radiolabeled alditols obtained by reductive beta-elimination in the presence of NaB(3)H(4). Both methods were applied for the analysis of the O-linked sugars in the mucins of T. cruzi CL 14 and revealed that they contained only N-acetylglucosamine and the disaccharide Galpbeta1-->4GlcNAc.

Animals↗
PubMed1998

Endothelial and fibroblast cell-derived heparan sulphate bind with differing affinity to basic fibroblast growth factor.

Heparan sulphate from endothelial cells (ECHS) has been shown to bind to bFGF with a lower affinity than that seen for 3T3 fibroblast HS (FHS). To investigate the structural reasons for the low affinity binding of ECHS to bFGF, enzymatic degradation of intact ECHS and FHS chains was undertaken. Filter binding assays showed ECHS heparinase III-resistant fragments 6-7 disaccharides in length and had affinity for bFGF equivalent to that of the intact ECHS chains. The largest resistant fragments from FHS, again 6-7 disaccharides in length, bound to bFGF with a similar affinity to the largest ECHS oligosaccharides, and they therefore have considerably lower affinity than seen for the intact FHS chains. Disaccharide compositional analysis of both ECHS and FHS oligosaccharides showed them to contain similar amounts of 2-O-, 6-O-, and N-sulphated disaccharides. These results suggest that the sulphation pattern within sulphated HS domains and their overall length are not the sole contributors to the binding of intact HS chains to bFGF. It is suggested that domain organisation and frequency of occurrence of large heparinase III-resistant oligosaccharides within intact chains play an important role not only in governing the maximum observed binding affinity of intact chains in the assay system used, but also in the regulation of other biological properties of HS.

3T3 Cells↗
PubMed2000

A specific structural alteration in the heparan sulphate of human glomerular basement membrane in diabetes.

AIMS/HYPOTHESIS: Heparan sulphate proteoglycan is an important component of the glomerular anionic filtration barrier and its reduced amount in diabetes contributes to glomerular dysfunction. The objective of this study was to determine if there is also an alteration in the sulphation pattern of the diabetic heparan sulphate chains. METHODS: The heparan sulphate in the glomerular basement membrane/mesangial matrix from human diabetic and nondiabetic kidneys obtained at autopsy was fragmented by a hydrazine/nitrous acid procedure and after radiolabelling with NaB[3H]4, the disaccharide products were chromatographically resolved and quantified. RESULTS: Six sulphated disaccharides were identified in both the diabetic and nondiabetic samples and the molar distribution of these was similar, with the notable exception of the iduronic acid-2-O-sulphatectl--> 4glucosamine-3-O-sulphate species which occurred in the diabetic glomeruli in less than half the amount as in the nondiabetic samples (9.0% compared to 18.7% of total sulphated disaccharides, p < 0.005). CONCLUSION/INTERPRETATION: 3-O-sulphated glucosamine is a rare constituent of heparan sulphate occurring usually in a glucuronic acidbeta1--> 4glucosamine-3-O-sulphate(+/- 6-O-sulphate) sequence within the antithrombin-binding domain. In the glomerular basement membrane where the 3-O-sulphated glucosamine is present in substantial amounts, however, it occurs exclusively in an iduronic acid-containing sequence. It is likely that the recently discovered 3-O-sulphotransferase variant which specifically acts on the iduronic acidalpha1--> 4glucosamine sequence is decreased in human diabetes and moreover that this unusual disaccharide could be a component of a specific heparan sulphate domain which interacts with bioactive proteins.

Aged↗