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Showing papers on "Keratan sulfate published in 1992"


Journal ArticleDOI
TL;DR: It is concluded that the release of aggrecan fragments from articular cartilage into the synovial fluid seen at all stages of human osteoarthritis is promoted by the action of a normal cartilage proteinase which cleaves the Glu 373-Ala 374 bond of the interglobular domain.
Abstract: Synovial fluid was collected from patients with recent knee injury and from patients with early or late stage osteoarthritis. Chondroitin sulfate-substituted aggrecan fragments present in these fluids, and in normal bovine synovial fluid, were purified by cesium chloride gradient centrifugation, enzymically deglycosylated and fractionated by gel filtration on Superose-12. Each sample contained two major aggrecan core protein populations with apparent molecular masses of ∼ 90 kD and 150 kD. For all samples, NH2-terminal analysis of both populations gave a single major sequence beginning ARGSV. This NH2 terminus results from cleavage of the human aggrecan core protein at the Glu 373-Ala 374 bond within the interglobular domain between the G1 and G2 domains. Cleavage at this site also occurs during control and interleukin-1 stimulated aggrecan catabolism in bovine cartilage explant cultures (Sandy, J., P. Neame, R. Boynton, and C. Flannery. 1991. J. Biol. Chem. 266:8683-8685). These results indicate that the major aggrecan fragments present in both osteoarthritic human synovial fluid and in normal bovine synovial fluid are large, being composed of a short NH2-terminal stretch of the interglobular domain, the G2 domain, the keratan sulfate domain, and variable lengths of the chondroitin sulfate domain(s). We conclude that the release of aggrecan fragments from articular cartilage into the synovial fluid seen at all stages of human osteoarthritis (Lohmander, L. S. 1991. Acta Orthop. Scand. 62:623-632) is promoted by the action of a normal cartilage proteinase which cleaves the Glu 373-Ala 374 bond of the interglobular domain. (Less)

407 citations


Journal ArticleDOI
TL;DR: Investigation on aggrecan the major proteoglycan of cartilage shows that in spite of a high keratan sulfate content the interglobular domain provides important sites for cleavage by different proteinases, including several members of the matrix metalloproteinase family.

292 citations


Journal ArticleDOI
TL;DR: Evidence is provided for the capacity of OA cartilage to synthesize new aggrecan molecules to replace those damaged and lost by disease-related changes and defines two phases of PG change in OA: an early predominantly degenerate phase I followed by a net reparative phase II accompanied by net loss of these molecules.
Abstract: Changes in the structure of the proteoglycan aggrecan (PG) of articular cartilage were determined immunochemically by RIA and gel chromatography and related to cartilage degeneration documented histologically by the Mankin grading system. Monoclonal antibodies to glycosaminoglycan epitopes were used. In all cartilages, three chondroitin sulfate (CS)-rich populations of large size were observed in addition to a smaller keratan sulfate (KS)-rich population. In grades 7-13 OA cartilages (phase II), molecules were significantly larger than the equivalent molecules of grades 2-6 (phase I). CS chain lengths remained unchanged. In most OA cartilages, a CS epitope 846 was elevated in content, this being most marked in phase II (mean: fivefold). Loss of uronic acid, KS, and hyaluronic acid were only pronounced in phase II OA because of variations in normal contents. Aggregation of PG was unchanged (50-60%) or reduced in OA cartilages, but molecules bearing epitope 846 exhibited almost complete aggregation in normal cartilages. This study provides evidence for the capacity of OA cartilage to synthesize new aggrecan molecules to replace those damaged and lost by disease-related changes. It also defines two phases of PG change in OA: an early predominantly degenerate phase I followed by a net reparative phase II accompanied by net loss of these molecules.

258 citations


Journal ArticleDOI
TL;DR: After immunization of mice with partially-purified heparan sulfate proteoglycan (HSPG) isolated from rat glomeruli, a monoclonal antibody (mAb JM-403) was obtained, which was directed against heparin sulfate (HS), the glycosaminoglycan side chain of HSPG.

235 citations


Journal ArticleDOI
TL;DR: The expression of lumican in tissues other than cornea indicates a broader role for lumican besides contributing to corneal transparency, andRadiolabeling and immunoprecipitation studies show that lumican core protein is also synthesized by these tissues.

232 citations


Journal ArticleDOI
TL;DR: The results emphasize the similarity of the newly synthesized proteoglycans secreted by cells grown in alginate beads to those synthesized by the neonate disc, and demonstrate the usefulness of this method as a microculture technique for disc cells.

219 citations


Journal ArticleDOI
TL;DR: The probable role of proteoglycans in normal glomerular cell function, and in progressive renal disease, will be presented as a harbinger of the significant role they can expect to play in diagnosis and therapy in the near future.
Abstract: Proteoglycans are a diverse group of proteins carrying one or more glycosaminoglycan side chains linked to the protein as O-glycosides. Our appreciation of these structures has matured from a curiosity about unusual structural glycoproteins, to confer upon them a central role in cell biology. The major classes of glycosaminoglycans are heparan sulfate and heparin, chondroitin and dermatan sulfates, keratan sulfate and hyaluronic acid. The latter is unique in that it does not contain sulfate residues, and appears to be synthesized, at least sometimes, free of a carrier protein. There is now a wealth of information on the ability of these structures to influence the growth and development of cells and tissues. Many direct and specific effects of proteoglycans will undoubtedly be found, and there are likely to be indirect effects of the glycosaminoglycans relating to their polyelectrolyte nature. Convincing arguments that biological activity resides in certain proteoglycan core proteins are also appearing. The following discussion concerns the role of proteoglycans in the regulation and action of autocrine and polypeptide growth factors, direct mitogenic and antimitogenic actions of glycosaminoglycans, the role of these structures in regulating gene expression, and the biological activities of proteoglycan core proteins. The probable role of proteoglycans in normal glomerular cell function, and in progressive renal disease, will be presented as a harbinger of the significant role we can expect them to play in diagnosis and therapy in the near future.

199 citations


Journal Article
TL;DR: The results indicate that the synthesis of proteoglycans by human corneal fibroblasts in culture is altered, resulting in increased production of basement membrane-associated proteoglyCans and decreased synthesis of Corneal stroma- associated proteogly cans.
Abstract: The proteoglycans produced by intact human corneas and corneal cells in culture were compared by characterizing the biosynthetically radiolabeled proteoglycans and by using antibodies to detect their core proteins. Organ cultures of corneas primarily produce a keratan sulfate proteoglycan (KSPG) and a chondroitin and dermatan sulfate proteoglycan (decorin). Immunostaining with antibodies specific for the core proteins of KSPG and decorin showed that these proteoglycans are localized to the corneal stroma. The stroma also contained trace amounts of matrix that stained with antibodies to basement membrane heparan sulfate proteoglycan (perlecan) and laminin. Corneal fibroblasts in culture produced decorin, but the synthesis of KSPG appeared to be blocked at the level of core protein synthesis. Corneal fibroblasts in culture, however, produced perlecan in greater amounts than they did in organ cultures, and they synthesized both perlecan and laminin in greater amounts than did corneal epithelial cells in culture. These results indicate that the synthesis of proteoglycans by human corneal fibroblasts in culture is altered, resulting in increased production of basement membrane-associated proteoglycans and decreased synthesis of corneal stroma-associated proteoglycans.

98 citations


Journal ArticleDOI
TL;DR: Results indicate that molecules recognized by antibodies to glycosaminoglycans are present in the eggshell, and their localized distribution relative to the calcified matrix suggests that they may be involved in the regulation of mineral deposition.

93 citations


Journal ArticleDOI
TL;DR: The CNS antigen is similar, but not identical, to the cartilage antigen, and may represent another member of the family of high molecular weight CSPGs which bind to and aggregate with hyaluronic acid.

90 citations


Journal ArticleDOI
TL;DR: The results of this study suggest that adult chick corneas contain two isoforms of decorin: one containing C/DS side chains and the other, a hybrid, containing both C/ DS and KS side chains.

Journal ArticleDOI
TL;DR: Analysis of cartilage explants and synovial fluids indicates that at early stages of experimental OA, there is increased release of the proteoglycan aggregates of the articular cartilage.

Journal ArticleDOI
TL;DR: Two different chondroitin sulfate proteoglycans (CSPG) in embryonic chick brain were distinguished by immunoreactivity by suggesting that these two distinct core proteins are immunologically and biochemically unique translation products of two different CSPG genes.

Journal ArticleDOI
TL;DR: When hyaluronan eye drops were instilled after corneal epithelial removal with n-heptanol, hyaluronic acid stimulated wound closure in a dose-dependent manner, but its stimulatory efficacy was not dependent on molecular weight.
Abstract: Hyaluronan (hyaluronic acid) is a high molecular weight viscoelastic polymer which has been postulated to enhance wound healing. We investigated the dose and molecular weight (9 × 104 - 280 × 104) dependent effects of hyaluronan on the rate of migration of rabbit corneal epithelium in organ culture and on wound closure in vivo after debridement with n-heptanol. When corneal blocks were cultured with hyaluronan for 20 hours, distances of epithelial migration significantly increased over exposed stroma in proportion to hyaluronan concentration. However, there was no difference in the stimulatory action of hyaluronan on epithelial migration when corneal blocks were cultured at 1 mg/ml of hyaluronan irrespective of changes in the molecular weight range between 9 × 104 and 280 × 104. Glycosaminoglycans other than hyaluronan (chondroitin, chondroitin sulfate, keratan sulfate and heparan sulfate) failed to increase the epithelial migration. When hyaluronan eye drops were instilled after corneal epithelial remova...

Journal ArticleDOI
TL;DR: The 4/6-sulfate ratio of the galactosaminoglycans was increased, whereas the proportion of iduronic acid was markedly decreased, and this decrease was far more extensive than that observed in relation to age in normal tissue.
Abstract: Glycosaminoglycans in normal and osteoarthrotic temporomandibular joint disks were studied by means of high-performance liquid chromatography methods. Normal disk tissue contains galactosaminoglycans (chondroitin sulfate and dermatan sulfate) as the main polysaccharides and with smaller amounts of hyaluronate and heparan sulfate. The galactosaminoglycans are mainly sulfated in 6-position, and some of the disaccharides contain iduronic acid. There was a slight general variation in glycosaminoglycan concentration with increasing age. In the severely arthrotic disks the content of glycosaminoglycans was considerably lower than in normal disk tissue. This decrease was far more extensive than that observed in relation to age in normal tissue. The 4/6-sulfate ratio of the galactosaminoglycans was increased, whereas the proportion of iduronic acid was markedly decreased.

Journal ArticleDOI
R.A. Hahn1, D.E. Birk1
TL;DR: Biochemical and biochemical data suggest that dermatan sulfate proteoglycans are not involved in the regulation of corneal collagen fibril diameter, but are important in the fibrill-fibril spacing as well as in lamellar organization, and cohesiveness.
Abstract: Corneal transparency is dependent upon the development of an organized extracellular matrix containing small diameter collagen fibrils with regular spacing, organized as orthogonal lamellae. Proteoglycan-collagen interactions have been implicated in the regulation of collagen fibrillogenesis and matrix assembly. To determine the role of dermatan sulfate proteoglycan in the development and organization of the secondary corneal stroma, its synthesis was disrupted using beta-D xyloside. The secondary corneal stroma contains two different proteoglycans, dermatan sulfate and keratan sulfate proteoglycan. beta-D xyloside interferes with xylose-mediated O-linked proteoglycan synthesis, and thus disrupts dermatan sulfate proteoglycan synthesis. Corneal keratan sulfate proteoglycan, a mannose-mediated N-linked proteoglycan, should not be altered. Biochemical analysis of corneas treated both in vitro and in ovo revealed a reduced synthesis of normally glycosylated dermatan sulfate proteoglycans and an increased synthesis of free xyloside-dermatan sulfate glycosaminoglycans. Keratan sulfate proteoglycan synthesis was unaltered in both cases. Corneal stromas were studied using histochemistry and electron microscopy after in ovo treatment with beta-D xyloside. The observed biochemical alterations in dermatan sulfate proteoglycans translated into disruptions in the organization of beta-D xyloside-treated stromas. There was a reduction in the histochemical staining of proteoglycans, but no alteration in collagen fibril diameter. In addition, focal alterations in collagen fibril packing, and a disruption of lamellar organization were observed in beta-D xyloside-treated corneas. These data suggest that dermatan sulfate proteoglycans are not involved in the regulation of corneal collagen fibril diameter, but are important in the fibril-fibril spacing as well as in lamellar organization, and cohesiveness.

Journal ArticleDOI
TL;DR: Results suggest that HA is abundantly synthesized and secreted in chondrocytes located in the transition between the superficial and middle zones of the rabbit tibia.
Abstract: To demonstrate the intra- and extracellular localization of hyaluronic acid (HA) in articular cartilage of the rabbit tibia, biotinylated HA binding region, which specifically binds to the HA molecule, was applied to the tissue. In comparison with the localization of HA, that of chondroitin sulfate (CS), keratan sulfate (KS), and the protein core (PC) of the proteoglycan was examined by immunohistochemistry. Strong positive staining for HA was detected in chondrocytes located in the transition between the superficial and middle zones of the tissue. Pre-treatment with chondroitinase ABC, keratanase II, or trypsin enhanced the stainability for HA in peri- and intercellular matrices. Immunohistochemistry with or without enzymatic pre-treatment demonstrated that immunoreactivity for CS, KS, and PC was distinctly discerned in chondrocytes and in the extracellular matrix located in the middle and deep zones. In particular, the immunoreactivity for KS and PC was augmented by pre-treatment with chondroitinase ABC not only in chondrocytes but in the extracellular matrix located in the middle and deep zones. Microbiochemical analysis corresponded well with histochemical and immunohistochemical results. These results suggest that HA is abundantly synthesized and secreted in chondrocytes located in the transition between the superficial and middle zones.

Journal ArticleDOI
TL;DR: Comparison of the oligosaccharide maps suggests that the KS chains from both parts of the aggrecan molecule have the same structure.
Abstract: The hyaluronan-binding region (HABR) was prepared from pig laryngeal cartilage aggrecan and the amino acid sequence was determined. The HABR had two N-termini: one N-terminal sequence was Val-Glu-Val-Ser-Glu-Pro (367 amino acids in total), and a second N-terminal sequence (Ala-Ile-Ser-Val-Glu-Val; 370 amino acids in total) was found to arise due to alternate cleavage by the signal peptidase. The N-linked oligosaccharides were analysed by examining their reactivity with a series of lectins. It was found that the N-linked oligosaccharide on loop A was of the mannose type, while that on loop B was of the complex type. No reactivity was detected between the N-linked oligosaccharide on loop B' and any of the lectins. The location of keratan sulphate (KS) in the HABR was determined by Edman degradation of the immobilized KS-containing peptide. The released amino acid derivatives were collected and tested for the presence of epitope to antibody 5-D-4. On the basis of 5-D-4 reactivity and sequencing yields, the KS chains are attached to threonine residues 352 and 357. There is no KS at threonine-355. This site is not in fact in G1, but about 16 amino acid residues into the interglobular domain. Comparison of the structure of the KS chain from the HABR and from the KS domain of pig laryngeal cartilage aggrecan was made by separation on polyacrylamide gels of the oligosaccharides arising from digestion with keratanase. Comparison of the oligosaccharide maps suggests that the KS chains from both parts of the aggrecan molecule have the same structure.

Journal ArticleDOI
TL;DR: The assembly and deposition of small-diameter fibrils with a collagen composition and structure identical to that seen in the corneal stroma in the absence of proteoglycans typical of the secondary cornean stroma imply that although proteoglycan-collagen interactions may function in the establishment of interfibrillar spacing and lamellar organization, collagen-Collagen interactions are the major parameter in the regulation of fibril diameter.

Journal ArticleDOI
TL;DR: Changes in matrix glycosaminoglycan content, both in the different zones and within zones, indicate constant subtle alterations in chondrocyte metabolic products as they proceed through their life cycle of proliferation, maturation, and hypertrophy.
Abstract: Monoclonal antibodies were used in this study to immunolocate glycosaminoglycans throughout the human growth plate. Chondroitin-4-sulfate, chondroitin-6-sulfate, and keratan sulfate were observed in the extracellular matrix of all zones of the growth plate and persisted into the cartilage trabeculae of newly formed metaphyseal bone. Also present in the extracellular matrix was an oversulfated chondroitin/dermatan sulfate glycosaminoglycan which appeared to be specific to the proliferative and hypertrophic zones of the growth plate. As with the other extracellular matrix molecules, this epitope persisted into the cartilage trabeculae of the metaphyseal bone. Zonal differences between the extracellular and pericellular or lacunae matrix were also observed. The hypertrophic chondrocytes appeared to synthesize chondroitin sulfate chains containing a non-reducing terminal 6-sulfated disaccharide, which were located in areas immediately adjacent to the cells. This epitope was not found to any significant extent...

Journal ArticleDOI
TL;DR: A novel CNS specific keratan sulfate proteoglycan is identified by a monoclonal antibody (mAb) TED15, being present in the optic nerve but absent from the retina.

Journal ArticleDOI
TL;DR: The results suggest that HA is synthesized in and secreted from epithelial and stromal cells of rabbit cornea, while the localization of HA in the apical surface of the endothelium is closely associated with that of CD44.
Abstract: To demonstrate the localization of hyaluronic acid (HA) in rabbit cornea, the biotinylated HA-binding region, which specifically binds to the HA molecule, was applied to the tissue. Localization of chondroitin sulfate (CS) and CD44, a possible cell surface receptor for HA, were also examined by immunohistochemistry. The stainability of HA changed depending on the fixatives used. Reaction products for HA were distinctly detected in epithelial cells and stromal keratocytes, but faintly in the extracellular matrix of the stroma when unfixed cryosections were applied. No positive reaction was found in the endothelium, except that the positive deposits formed a continuous layer on the apical surface of the endothelium. Electron microscopy using samples fixed with 2% paraformaldehyde revealed gold particles indicating HA labeling the intercellular space of the epithelium and stromal extracellular matrix. No intracellular deposition was detected in epithelial cells, whereas the gold labeling was seen in vacuolar structures of stromal keratocytes. Immunodeposits for CS were intensely localized in the epithelium and stroma, and weakly in the endothelium. Immunoreactivity for CD44 was found in the epithelial, endothelial and stromal cells. In particular, immuno-deposits for CD44 were detected in basal parts of epithelial cells, while they were localized in the apical surface of endothelial cells. These results suggest that HA is synthesized in and secreted from epithelial and stromal cells of rabbit cornea, while the localization of HA in the apical surface of the endothelium is closely associated with that of CD44. Moreover, the presence of CS in corneal tissue may play a role in its transparency, as has been suggested for keratan sulfate and dermatan sulfate.

Journal ArticleDOI
TL;DR: Monoclonal antibodies raised against rat chondrosarcoma aggrecan that was either denatured through reduction and alkylation or partially deglycosylated through chondroitinase ABC digestion or alkali elimination confirm the occurrence of multiple repeated epitopes throughout the different domain structures of aggre can.

Journal Article
TL;DR: The results suggest that sulfated glycans bind to a Thy-1 site distinct from that with which this molecule interacts with its heterophilic ligand, which could modulate the binding of rat mAb directed at spatially distinct Thy- 1 epitopes.
Abstract: Thy-1 is a major brain cell surface glycoprotein of adult mammal species also expressed in rodent thymus. Despite extensive studies, the function(s) of this molecule has remained so far ill defined. We have recently shown that Thy-1 was involved in the adhesion of mouse thymocytes to thymic epithelium through a specific interaction with a heterophilic ligand(s) expressed on the epithelial cell surface. In the present study, we aimed at evaluating the interaction of sulfated glycans with mouse Thy-1, as well as its consequence on Thy-1-mediated thymic lympho-epithelial cell interaction. It was shown that 125I-labeled Thy-1 directly bound to immobilized heparin. Sulfated glycans such as pentosan sulfate, dextran sulfate, and fucoidan were found to strongly inhibit the binding of Thy-1 to heparin. In contrast, chondroitin sulfate, keratan sulfate, and heparan sulfate were not inhibitory. Sulfated glycans (e.g., pentosan sulfate, assayed at a concentration of 50 micrograms/ml) completely blocked the Thy-1-dependent adhesion of T cells to a mouse thymic epithelial cell monolayer. To explore the mechanism of this inhibition, we compared the ability of T cell to adhere to mouse thymic epithelial cell monolayer or to sulfated glycans. Our results suggest that sulfated glycans bind to a Thy-1 site distinct from that with which this molecule interacts with its heterophilic ligand. Moreover, sulfate glycans could modulate the binding of rat mAb directed at spatially distinct Thy-1 epitopes. The present results identified a potential mechanism regulating Thy-1-mediated lympho-epithelial cell adhesion.

Journal ArticleDOI
TL;DR: The biochemical nature of the molecule described here, along with tissue distribution studies using GCTM-2, indicates that the antigen is not related to previously described keratan sulphate proteoglycans.
Abstract: We describe here the purification and partial characterization of a 200 kDa keratan sulphate proteoglycan found in the pericellular matrix of human embryonal carcinoma cells. Previously we have shown that this molecule is recognized by a monoclonal antibody (GCTM-2). The antigen was isolated using ion-exchange chromatography and gel filtration, purification being monitored by e.l.i.s.a. using GCTM-2. Metabolic labelling of GCT 27 C-4 embryonal carcinoma cells with sodium [35S]sulphate resulted in the incorporation of [35S]sulphate into the purified molecule. Throughout the purification procedure, the peaks of 35S radioactivity were coincident with the peaks of immunoreactivity, and this label was released both by digestion with keratanase and chondroitinase, confirming the proteoglycan nature of the antigen. The intact molecule ran as a single broad band of 200 kDa, which has been identified by silver staining and immunoblotting following gel electrophoresis. Amino acid analysis of the purified antigen indicated a high content of serine, glycine and aspartic acid/asparagine residues. Visualization by rotary-shadowing electron microscopy suggests that the purified material forms large aggregates, even under denaturing conditions. Deglycosylation of this preparation with trifluoromethanesulphonic acid yielded a major band of 55 kDa and a minor band of 48 kDa. The biochemical nature of the molecule described here, along with tissue distribution studies using GCTM-2, indicates that the antigen is not related to previously described keratan sulphate proteoglycans.

Journal ArticleDOI
TL;DR: Results suggest that leucocyte elastase cleaves the core protein of aggrecan between valine 397 and isoleucine 398, which are located in the interglobular domain linking the G1 and G2 domains of the coreprotein of aggREcan.

Journal ArticleDOI
TL;DR: The influence of (a) antigen structure, (b) type of monoclonal antibody, and (c) antibody bivalency on the immunochemical detection and quantification of keratan sulfate (KS) from aggrecan has been studied.

Journal ArticleDOI
TL;DR: The structure of this oligosaccharide shows that keratan sulphate chains from bovine intervertebral disc have non-reducing termini with N-acetylneuraminic acid linked alpha(2----6) as well as alpha( 2----3) to an unsulphated galactose.
Abstract: Peptido-keratan sulphate fragments were isolated from the nucleus pulposus of bovine intervertebral discs (2-year-old animals) after digestion with chondroitin ABC lyase followed by digestion with diphenylcarbamoyl chloride-treated trypsin of A1D1 proteoglycans and gel-permeation chromatography on Sepharose CL-6B. The peptido-keratan sulphate fragments were subjected to alkaline borohydride reduction. The reduced chains were treated with keratanase in the presence of the sialidase inhibitor 2,3-dehydro-2-deoxy-N-acetylneuraminic acid, and the digest was subjected to alkaline borohydride reduction. This produced oligosaccharides with galactitol at their reducing ends. This reduced digest was chromatographed on a Nucleosil 5 SB anion-exchange column and individual oligosaccharides were isolated. One of these was shown by 600 MHz 1H-n.m.r. spectroscopy to have the following structure: NeuAc alpha 2-6Gal beta 1-4GlcNAc(6-SO4)beta 1-3Gal-ol The structure of this oligosaccharide shows that keratan sulphate chains from bovine intervertebral disc have non-reducing termini with N-acetylneuraminic acid linked alpha(2----6) as well as alpha(2----3) to an unsulphated galactose.

Journal ArticleDOI
TL;DR: The rationale for the contention that this elevation in the rate of proteoglycan turnover precedes clinical evidence of degenerative changes may predispose adult humans to polyarticular osteoarthritis is discussed.

Journal ArticleDOI
TL;DR: Alkaline borohydride-reduced keratan sulphate chains from bovine articular cartilage (6-8-year-old animals) were fragmented by an anhydrous hydrazine/nitrous acid procedure, providing a sensitive fingerprinting technique for the assay of KS composition and sub-populations.
Abstract: Alkaline borohydride-reduced keratan sulphate (KS) chains from bovine articular cartilage (6-8-year-old animals) were fragmented by an anhydrous hydrazine/nitrous acid procedure, previously used on KS by Hopwood & Elliott to isolate the major disaccharides from the poly-N-acetyl-lactosamine repeat sequence [Hopwood & Elliott (1983) Carbohydr. Res. 117, 263-274]. The resulting oligosaccharides were reduced with NaB3H4 or NaBH4 and subjected to ion-exchange chromatography on a Nucleosil 5SB column. In addition to the major disaccharides, two fucose-containing oligosaccharides were examined by high-field 1H n.m.r. spectroscopy, and shown to have the following structures (where AnManOH is 2,5-anhydro-D-mannitol): [formula: see text] It is evident that the presence of fucose protects the N-acetylglucosamine residue from de-N-acetylation, and therefore fragments are produced which preserve the immediate environment of the fucose residue. It may be of biosynthetic significance that these two oligosaccharides contain an unsulphated galactose on the non-reducing side of the fucose residue. The hydrazine/nitrous acid/NaB3H4 method followed by h.p.l.c. provides a sensitive fingerprinting technique for the assay of KS composition and sub-populations.