scholarly journals Molecular distinctions between heparan sulphate and heparin. Analysis of sulphation patterns indicates that heparan sulphate and heparin are separate families of N-sulphated polysaccharides

1985 ◽  
Vol 230 (3) ◽  
pp. 665-674 ◽  
Author(s):  
J T Gallagher ◽  
A Walker

Heparan sulphate and heparin are chemically related alpha β-linked glycosaminoglycans composed of alternating sequences of glucosamine and uronic acid. The amino sugars may be N-acetylated or N-sulphated, and the latter substituent is unique to these two polysaccharides. Although there is general agreement that heparan sulphate is usually less sulphated than heparin, reproducible differences in their molecular structure have been difficult to identify. We suggest that this is because most of the analytical data have been obtained with degraded materials that are not necessarily representative of complete polysaccharide chains. In the present study intact heparan sulphates, labelled biosynthetically with [3H]glucosamine and Na2(35)SO4, were isolated from the surface membranes of several types of cells in culture. The polysaccharide structure was analysed by complete HNO2 hydrolysis followed by fractionation of the products by gel filtration and high-voltage electrophoresis. Results showed that in all heparan sulphates there were approximately equal numbers of N-sulpho and N-acetyl substituents, arranged in a similar, predominantly segregated, manner along the polysaccharide chain. O-Sulphate groups were in close proximity to the N-sulphate groups but, unlike the latter, the number of O-sulphate groups could vary considerably in heparan sulphates of different cellular origins ranging from 20 to 75 O-sulphate groups per 100 disaccharide units. Inspection of the published data on heparin showed that the N-sulphate frequency was very high (greater than 80% of the glucosamine residues are N-sulphated) and the concentration of O-sulphate groups exceeded that of the N-sulphate groups. We conclude from these and other observations that heparan sulphate and heparin are separate families of N-sulphated glycosaminoglycans.

1983 ◽  
Vol 211 (3) ◽  
pp. 677-682 ◽  
Author(s):  
P N Sanderson ◽  
I A Nieduszynski ◽  
T N Huckerby

Oligosaccharides with the general structure UA-(GlcNAc-GlcUA-)m-aManOH (m = 1-5) (where UA represents uronic acid, GlcNAc N-acetylglucosamine, GlcUA glucuronic acid and aManOH anhydromannitol) were prepared from low-sulphated heparan sulphates of bovine lung origin by nitrous acid deaminative cleavage followed by reduction. Analysis of the methylene signals in the 100 MHz 13C-n.m.r. spectrum of the tetrasaccharide (m = 1) shows that, whereas the extent of C-6 O-sulphation in the GlcNAc is approx. 65%, in the aManOH [formerly a GlcNSO3 (N-sulphoglucosamine) residue in the parent heparan sulphate] it is only approx. 10%. In the higher oligosaccharides (m = 2-5) the gross extent of C-6 O-sulphation of GlcNAc residues falls systematically with increasing oligosaccharide size, whereas that in the aManOH residues remains below 10%. There is also evidence that the C-6 O-sulphation of the GlcNAc residues is confined to the GlcNAc residue adjacent to the non-reducing terminal uronic acid residue. It is therefore tentatively proposed that the GlcNAc in the sequence -GlcNSO3-UA-GlcNAc- might be a favoured substrate for the 6-O-sulphotransferase. It is concluded that in the low-sulphated heparan sulphates GlcNSO3 residues that do not occur in (GlcNSO3-UA-)n blocks tend to have a significantly smaller extent of C-6 O-sulphation than do GlcNAc residues that occur in -GlcNSO3-UA-GlcNAc-GlcUA-GlcNSO3-sequences.


1984 ◽  
Vol 223 (2) ◽  
pp. 495-505 ◽  
Author(s):  
P N Sanderson ◽  
T N Huckerby ◽  
I A Nieduszynski

Tetrasaccharides with the general structure UA-GlcNAc-GlcUA-aManOH (where UA represents uronate, GlcNAc N-acetylglucosamine, GlcUA glucuronate and aManOH anhydromannitol) were prepared from low-sulphated heparan sulphates of bovine lung origin by complete nitrous acid deaminative cleavage followed by reduction and fractionated by gel filtration. Ion-exchange chromatography of the tetrasaccharides yielded three major fractions in approximate yields of 37%, 45% and 14%. These were shown to be non-, mono- and di-sulphated respectively. Complete structural characterization of the tetrasaccharide fractions by quantitative high-field n.m.r. spectroscopy showed that each fraction contained only two discrete species and led to the following observations. (1) All of the uronate residues in the tetrasaccharides (and in larger oligosaccharides) are unsulphated, and hence sulphated iduronate [IdUA(2SO3)] must occur exclusively within -GlcNSO3-IdUA(2SO3)-GlcNSO3- sequences (where GlcNSO3 represents N-sulpho-glucosamine) in the parent polymers. (2) The GlcNAc residues in the tetrasaccharides are more highly C-6-O-sulphated than are the aManOH residues, and furthermore sulphation on the aManOH appears to occur only where the GlcNAc is also sulphated. (3) Where the GlcNAc is C-6-O-sulphated, iduronate is the major non-reducing terminal residue, whereas glucuronate predominates in this position if the GlcNAc is unsulphated. The quantitative data obtained are used to determine the degree of C-6-O-sulphation of glucosamine residues in specific sequences within the parent heparan sulphates.


1970 ◽  
Vol 119 (5) ◽  
pp. 885-893 ◽  
Author(s):  
T. E. Hardingham ◽  
C. F. Phelps

1. The incorporation of [35S]sulphate in vivo into the acid-soluble intermediates extracted from young rat skin showed three sulphated hexosamine-containing components. 2. The rates of synthesis of these components were determined in vivo by measuring the incorporation of radioactivity from [U-14C]glucose into their isolated hexosamine moieties. 3. The incorporation of radioactivity from [U-14C]glucose into the isolated hexosamine and uronic acid moieties of the acid glycosaminoglycans was also measured. These results, combined with those obtained on the intermediary pathways of hexosamine and uronic acid biosynthesis previously determined in this tissue, indicated that the acid-soluble sulphated hexosamine-containing components were not precursors of the sulphated hexosamine found in the acid glycosaminoglycans. 4. The rates of synthesis of the acid glycosaminoglycan fractions were calculated from the incorporation of radioactivity from [U-14C]glucose into the hexosamine moiety. The sulphated components containing principally dermatan sulphate, chondroitin 6-sulphate and in smaller amounts, chondroitin 4-sulphate, heparan sulphate and heparin appeared to be turning over about twice as rapidly as hyaluronic acid and about four times as rapidly as the small keratan sulphate fraction. The relative rates of synthesis of the sulphated glycosaminoglycans were calculated from the incorporation of [35S]sulphate and were in agreement with those from 14C-labelling studies.


1978 ◽  
Vol 56 (5) ◽  
pp. 339-344 ◽  
Author(s):  
M. W. C. Hatton ◽  
E. Regoeczi ◽  
H. Kaur

After proteolytic digestion of bovine transferrin (phenotype AA), a glycopeptide fraction was isolated by gel filtration and high-voltage electrophoresis. Two glycopeptide bands were recovered, each of which contained one residue of aspartic acid, two of serine, two of galactose, three of mannose, and four of N-acetyl glucosamine together with some fucose. However, the bands differed with respect to sialic acid content (two and three residues respectively). Using the same isolation procedures, a commercial sample of human transferrin yielded four glycopeptide bands (two major, two minor) on high-voltage electrophoresis. On analysis, the two major bands differed in amino-acid residues but their carbohydrate compositions were very similar. The analyses largely resembled previously published analytical data for two human transferrin glycopeptides (Jamieson, G. A., Jett, M. &DeBernardo, S. L. (1971) J. Biol. Chem. 246, 3686–3693; Spik, G., Bayard, B., Fournet, B., Strecker. G., Bouquelet, S. &Montreuil, J. (1975) FEBS Lett. 50, 296–299) and the carbohydrate analyses showed many similarities to the bovine transferrin glycopeptide. From these data and earlier observations made on bovine and human transferrins (Hatton, M. W. C, Regoeczi, E. &Wong, K.-L. (1974) Can. J. Biochem. 52, 845–853), we have concluded that, in contrast with human transferrin, bovine transferrin contains only one heterosaccharide chain per molecule.Following tritiation, bovine transferrin asialoglycopeptide was compared with asialoglycopeptides from other serum proteins for their affinity to the rat liver in vivo. Considerable differences were observed and the following order of binding was established for the asialoglycopeptide preparations: bovine transferrin < human transferrin [Formula: see text] bovine fetuin [Formula: see text] human α1-acid glycoprotein.


1980 ◽  
Vol 191 (1) ◽  
pp. 103-110 ◽  
Author(s):  
Ingrid Sjöberg ◽  
Lars-Ȧke Fransson

1. 3H- and 35S-labelled heparan sulphate was isolated from monolayers of human lung fibroblasts and subjected to degradations by (a) deaminative cleavage and (b) periodate oxidation/alkaline elimination. Fragments were resolved by gel- and ion-exchange-chromatography. 2. Deaminative cleavage of the radioactive glycan afforded mainly disaccharides with a low content of ester-sulphate and free sulphate, indicating that a large part (approx. 80%) of the repeating units consisted of uronosyl-glucosamine-N-sulphate. Blocks of non-sulphated [glucuronosyl-N-acetyl glucosamine] repeats (3–4 consecutive units) accounted for the remainder of the chains. 3. By selective oxidation of glucuronic acid residues associated with N-acetylglucosamine, followed by scission in alkali, the radioactive glycan was degraded into a series of fragments. The glucuronosyl-N-acetylglucosamine-containing block regions yielded a compound N-acetylglucosamine–R, where R is the remnant of an oxidized and degraded glucuronic acid. Periodate-insensitive uronic acid residues were recovered in saccharides of the general structure glucosamine–(uronic acid–glucosamine)n–R. 4. Further degradations of these saccharides via deaminative cleavage and re-oxidations with periodate revealed that iduronic acid may be located in sequences such as glucosamine-N-sulphate→iduronic acid→N-acetylglucosamine. Occasionally the iduronic acid was sulphated. Blocks of iduronic acid-containing repeats may contain up to five consecutive units. Alternating arrangements of iduronic acid- and glucuronic acid-containing repeats were also observed. 5. 3H- and 35S-labelled heparan sulphates from sequential extracts of fibroblasts (medium, EDTA, trypsin digest, dithiothreitol extract, cell-soluble and cell-insoluble material) afforded similar profiles after both periodate oxidation/alkaline elimination and deaminative cleavage.


1987 ◽  
Vol 248 (3) ◽  
pp. 889-896 ◽  
Author(s):  
F A Ofosu ◽  
G J Modi ◽  
M A Blajchman ◽  
M R Buchanan ◽  
E A Johnson

Heparan sulphate and dermatan sulphate have both antithrombotic and anticoagulant properties. These are, however, significantly weaker than those of a comparable amount of standard pig mucosal heparin. Antithrombotic and anticoagulant effects of glycosaminoglycans depend on their ability to catalyse the inhibition of thrombin and/or to inhibit the activation of prothrombin. Since heparan sulphate and dermatan sulphate are less sulphated than unfractionated heparin, we investigated whether the decreased sulphation contributes to the lower antithrombotic and anticoagulant activities compared with standard heparin. To do this, we compared the anticoagulant activities of heparan sulphate and dermatan sulphate with those of their derivatives resulphated in vitro. The ratio of sulphate to carboxylate in these resulphated heparan sulphate and dermatan sulphate derivatives was approximately twice that of the parent compounds and similar to that of standard heparin. Anticoagulant effects were assessed by determining (a) the catalytic effects of each glycosaminoglycan on the inhibition of thrombin added to plasma, and (b) the ability of each glycosaminoglycan to inhibit the activation of 125I-prothrombin in plasma. The least sulphated glycosaminoglycans were least able to catalyse the inhibition of thrombin added to plasma and to inhibit the activation of prothrombin. Furthermore, increasing the degree of sulphation improved the catalytic effects of glycosaminoglycans on the inhibition of thrombin by heparin cofactor II in plasma. The degree of sulphation therefore appears to be an important functional property that contributes significantly to the anticoagulant effects of the two glycosaminoglycans.


1969 ◽  
Vol 15 (6) ◽  
pp. 555-561 ◽  
Author(s):  
P. W. Fardy ◽  
B. H. Matheson ◽  
R. W. Reed

Additional studies were undertaken on the nature of a nephrotoxic agent found in the culture filtrates of certain group A streptococci. A commercially available dehydrated medium proved satisfactory for the production of the active material. Gel filtration was used to divide polypeptide extracts, prepared from the dialyzable portion of culture filtrates, into two major fractions. One of these, representing the higher molecular weight components, contained most of the nephrotoxic activity as evidenced by the development of hypertension and acute glomerulonephritis in rabbits injected with this fraction.Physical and chemical studies indicated that the active fraction consisted of at least four polypeptide components separable by high voltage electrophoresis on paper. Automatic amino acid analysis of an acid hydrolysate of this fraction revealed 17 different amino acids. Carbohydrate was not detected by anthrone and orcinol tests.No relationship was established between this streptococcal nephrotoxic agent and other streptococcal constituents which have been implicated in acute glomerulonephritis.


1997 ◽  
Vol 324 (2) ◽  
pp. 473-479 ◽  
Author(s):  
Rolando E. VILAR ◽  
Dineshchandra GHAEL ◽  
Min LI ◽  
Devan D. BHAGAT ◽  
Lisa M. ARRIGO ◽  
...  

NO is a bioactive free radical produced by NO synthase in various tissues including vascular endothelium. One of the degradation products of NO is HNO2, an agent known to degrade heparin and heparan sulphate. This report documents degradation of heparin by cultured endothelial-cell-derived as well as exogenous NO. An exogenous narrow molecular-mass preparation of heparin was recovered from the medium of cultured endothelial cells using strong-anion exchange. In addition, another narrow molecular-mass preparation of heparin was gassed with exogenous NO under argon. Degradation was evaluated by gel-filtration chromatography. Since HNO2 degrades heparin under acidic conditions, the reaction with NO gas was studied under various pH conditions. The results show that the degradation of exogenous heparin by endothelial cells is inhibited by NO synthase inhibitors. Exogenous NO gas at concentrations as low as 400 p.p.m. degrades heparin and heparan sulphate. Exogenous NO degrades heparin at neutral as well as acidic pH. Endothelial-cell-derived NO, as well as exogenous NO gas, did not degrade hyaluronan, an unrelated glycosaminoglycan that resists HNO2 degradation. Peroxynitrite, a metabolic product of the reaction of NO with superoxide, is an agent that degrades hyaluronan; however, peroxynitrite did not degrade heparin. Thus endothelial-cell-derived NO is capable of degrading heparin and heparan sulphate via HNO2 rather than peroxynitrite. These observations may be relevant to various pathophysiological processes in which extracellular matrix is degraded, such as bone development, apoptosis, tissue damage from inflammatory responses and possible release of growth factors and cytokines.


1994 ◽  
Vol 159 ◽  
pp. 518-518
Author(s):  
I.I. Pronik

The flux of narrow 5007 Å [OIII] forbidden line during last 20 years is accepted as a bench-mark for calibration of the continuum and broad-lines fluxes in AGN. But one can not get away from the problem of the forbidden lines variability in these objects. The first report were published by Bardin et al. (1967). Some of the results are revieved by V. Pronik, I. Pronik (1988, 1992). There were 4 years monitoring of [OIII] fluxes variability in the Seyfert galaxy NGC 1275 nucleus (Pronik et al., 1990). Now we reexamine the published data of W. Zheng et al. (1986, 1987, 1988), discussed earlier in supposition of forbidden lines constant in spectra of 11 low-redshifted QSOs. Maximal calibration coefficients adopted by W. Zheng et al. in supposition of [OIII] lines constant were in the interval 2.0–3.6. On the other hand the fluxes errors are about 15%. Disagreement is very high. This is one of the arguments in the forbidden lines variability Tightness.


1983 ◽  
Vol 215 (1) ◽  
pp. 107-116 ◽  
Author(s):  
J T Gallagher ◽  
N Gasiunas ◽  
S L Schor

Human skin fibroblasts cultured on collagen gels produced two dermatan sulphate species, one, enriched in iduronic acid residues, that bound specifically to the collagenous fibres of the gel, the other, enriched in glucuronic acid, that accumulated in the culture medium. Collagen-binding and collagen-non-binding dermatan sulphates were also produced by cells grown on plastic surfaces, but in these cultures each constituent was released into the growth medium. Net synthesis of dermatan sulphate was 3-fold higher in cells maintained on collagen gels. In contrast, heparan sulphate synthesis was not influenced by the nature of the culture surface. The concentration of heparan sulphate in surface-membrane extracts was similar for cells grown on plastic and on collagen gels, but cells cultured on collagen showed a notable increase in the content of surface-membrane dermatan sulphate. The patterns of synthesis and distribution of sulphated glycosaminoglycans observed in skin fibroblasts maintained on collagen gels may reflect differentiated cellular functions.


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