Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.6.4 (chondroitinase)
 2,039 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Since the 1960s, the loss of sulfomucin from colonic epithelium has been considered to be an indicator of an early stage of carcinogenesis; yet, the biochemical basis for this phenomenon has never been elucidated. We recently prepared a monoclonal antibody (mAb) 91.9H that immunoprecipitates the normal colonic mucins metabolically incorporating [35S]-sulfate. This mouse IgG1 antibody did not cross-react with colon carcinoma mucins that lack sulfate groups. Using normal colonic epithelia unlabeled or radiolabeled with [35S]sulfate and [3H]glucosamine, we purified a high molecular weight glycoprotein that reacts with mAb 91.9H. This was achieved by a combination of DEAE-cellulose anion-exchange chromatography, consecutive treatments with chondroitinase ABC plus heparitinase and with sodium dodecyl sulfate plus 2-mercaptoethanol, and gel filtration on Sepharose CL-2B in the presence of 8 M urea. Antibody reactivity was found in acidic but not neutral high molecular weight glycoproteins. After Sepharose CL-2B fractionation, the mAb 91.9H-reactive fractions consisted of a component with an approximate molecular weight of 500,000-900,000. A purified sulfomucin contained protein, neutral sugar, amino sugar, sialic acid, and sulfate in an approximate ratio of 2.5:1.0:1.1:0.4:0.5. The polypeptide portion was rich in hydrophilic amino acids, particularly threonine. Binding of mAb 91.9H in solid-phase assays was inhibited to 50% by purified normal colon acidic mucin at doses of 5-50 micrograms/ml, depending on different preparations. Various glycosaminoglycans or sulfatides did not show inhibitory activity. Sulfomucin reactivity with mAb 91.9H, as determined by solid-phase-binding inhibition and by dot blot assays, was significantly reduced by chemical desulfation of sulfomucins with anhydrous hydrochloric acid, suggesting that sulfate groups served as a portion of the immunochemical determinant for this antibody. Sulfate residues were apparently linked to alkaline-sensitive carbohydrate chains, but alkaline-released carbohydrate chains did not react with mAb 91.9H. Immunohistochemical examinations showed that mAb 91.9H bound normal colonic epithelial cells, which also stained with high-iron diamine, more strongly than it bound colon carcinoma cells.
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PMID:Human colonic sulfomucin identified by a specific monoclonal antibody. 191 91

Sulfated macromolecules synthesized in tumor and mucosa tissues derived from colorectal cancer patients were labeled with [35S]sulfate and separated into two fractions on DEAE-Sephacel: the slightly acidic peak (peak I) was eluted with 0.2 M NaCl and the highly acidic peak (peak II) was eluted with 0.5 M NaCl. A total of 40 specimens, which included primary colon cancer, liver metastases, and normal mucosa obtained at surgery (16 patients), were examined regarding the amount of peak I and peak II. The amount of peak I significantly decreased in the order of normal mucosa greater than primary tumors greater than metastases, while the amount of peak II did not significantly change among the tissues. Peak I was mostly resistant to chondroitinase ABC and nitrous acid treatment under acidic conditions, whereas combined chondroitinase-sensitive materials and nitrous acid-sensitive materials were greater than 80% of the radioactivity in peak II. The major radioactive component of peak I migrated at a position corresponding to Mr greater than 300,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and became Mr less than 40,000 after alkaline borohydride treatment. The major component of peak I was likely to be a sulfated glycoprotein containing sulfate groups on alkaline labile carbohydrate chains. Peak II consisted of a mixture of heparan sulfate proteoglycans and chondroitin sulfate proteoglycans. Differential incorporation of [35S]sulfate into peak I among normal mucosa, primary colon carcinoma, and colon carcinoma metastasis was observed. Therefore, decreased peak I production may be a biochemical change associated with colorectal cancer progression and metastasis.
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PMID:Differential production of high molecular weight sulfated glycoproteins in normal colonic mucosa, primary colon carcinoma, and metastases. 356

The biosynthesis of proteoglycans in short term organ culture of human colon and colon carcinoma was studied. Proteoglycans, labeled with [35S]sulfate and [3H]serine, were extracted with either 4 M or 0.5 M guanidine HCl in the presence of protease inhibitors and sequentially purified by associative and dissociative CsCl density gradient ultracentrifugation. Normal colon synthesized two polydisperse classes of proteoglycans: a large heparan sulfate-containing monomer, with a Kav of 0.48 on Sepharose CL-2B and a small dermatan sulfate-containing monomer with a Kav of 0.65. A portion (25%) of the proteoglycans was found as aggregate when chromatographed under associative conditions, and the larger monomers interacted with hyaluronic acid to an extent greater than the smaller proteoglycans. Following papain or alkali treatment, the free glycosaminoglycan side chains of both monomers eluted as a single broad peak (Kav = 0.5) from Sepharose CL-6B, with an estimated Mr of 20 X 10(3). In contrast, colon carcinoma synthesized only one proteoglycan monomer, which aggregated to a limited extent (12%). This proteoglycan population, with a Kav of 0.7 on CL-2B, contained chondroitin sulfate as the major glycosaminoglycan (greater than 81%), with small amounts of dermatan sulfate. The glycosaminoglycans had an estimated Mr of 9 X 10(3), and the disaccharides released by chondroitinase ABC consisted of 32% 4-sulfate and 68% 6-sulfate. Electron microscopy of mixed proteoglycancytochrome c monolayers from the associative fractions of normal and neoplastic colon revealed aggregated complexes which were similar in over structure, although smaller than the proteoglycan aggregates from cartilage.
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PMID:Isolation and characterization of proteoglycans synthesized by human colon and colon carcinoma. 710 48

The biological activity of many cytokines is regulated by binding proteins present at the cell surface, in extracellular matrices or in soluble phase. We describe here a TGF-beta binding protein that is both an extracellular matrix and a cell surface protein. When intact extracellular matrices of HEP-G2 cells were affinity cross-linked with 125I-TGF-beta 1, two major binding components were seen: a 250-kD, proteoglycan-like molecule, presumed to be betaglycan, and a 60-kD protein. The 60-kD TGF-beta-binding protein was also present at the cell surface. It could be released from the cell surface by treating cells with high salt, heparin, chondroitin sulfate, heparitinase, or chondroitinase, indicating that it is bound to heparan sulfate and chondroitin sulfate proteoglycans. The 60-kD protein bound TGF-beta 1 with an apparent dissociation constant of 1.6 nM, and there were 30,000 binding sites per cell at the cell surface. In addition to the HEP-G2 cells and another hepatoma cell line, the 60-kD protein was also found in a human colon carcinoma (HT-29) cell line but not in rat kidney (NRK-49F) or human fibroblast (HUT-12) cell lines. The 60-kD protein could be extracted from cells containing it and transferred to the surface of previously negative cells. The 60-kD protein may serve to regulate the binding of TGF-beta to its signal transducing receptors by targeting TGF-beta to appropriate locations in the microenvironment of cells.
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PMID:A 60-kD protein mediates the binding of transforming growth factor-beta to cell surface and extracellular matrix proteoglycans. 833 95

The level of sulfo-Lea (SO3-3Gal beta 1-3(Fuc alpha 1-4)GlcNAc) epitope recognized by monoclonal antibody (mAb) 91.9H in hepatic metastasis of colon carcinoma is known to be lower than at the primary sites. We examined 19 human colon carcinoma cell lines for their production of this epitope. Sixteen cell lines were found to produce high M(r) components that metabolically incorporated [35S]sulfate and were resistant to heparitinase I and chondroitinase ABC, and 8 of them were reactive with mAb 91.9H as shown by western blotting analysis. These were all of the 4 cell lines derived from well differentiated primary tumors (HCCP-2998, LS174T, GEO, and CBS), 2 of 10 cell lines (DLD-1 and HCT116) from moderately to poorly differentiated primary tumors, and 2 of 5 cell lines (SW480 and HCC-M1544) from metastases. Incubation of LS174T cells with benzyl-N-acetyl-alpha-D-galactosaminide abrogated the incorporation of [35S]sulfate and the reactivity of mAb 91.9H with high M(r) components in the cell lysates. Sodium chlorate, which inhibits the formation of 3'-phosphoadenosine 5'-phosphosulfate, also inhibited the [35S]sulfate incorporation and reactivity with mAb 91.9H. These treatments did not change the incorporation of [14C]threonine into high M(r) components. These results indicated that sulfo-Lea epitopes were expressed on O-linked carbohydrate chains in sulfomucins. Immunohistochemical studies of tumor tissues in nude mice indicated that sulfo-Lea was expressed at the site of orthotopic transplantation in the cecum. The expression appeared to be suppressed in liver metastatic foci in nude mice.
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PMID:Expression of mucin-associated sulfo-Lea carbohydrate epitopes on human colon carcinoma cells. 1008 87

We examined whether chondroitin sulfates (CSs) exert inhibitory effects on heparanase (Hpse), the sole endoglycosidase that cleaves heparan sulfate (HS) and heparin, which also stimulates chemokine production. Hpse-mediated degradation of HS was suppressed in the presence of glycosaminoglycans derived from a squid cartilage and mouse bone marrow-derived mast cells, including the E unit of CS. Pretreatment of the chondroitin sulfate E (CS-E) with chondroitinase ABC abolished the inhibitory effect. Recombinant proteins that mimic pro-form and mature-form Hpse bound to the immobilized CS-E. Cellular responses as a result of Hpse-mediated binding, namely, uptake of Hpse by mast cells and Hpse-induced release of chemokine CCL2 from colon carcinoma cells, were also blocked by the CS-E. CS-E may regulate endogenous Hpse-mediated cellular functions by inhibiting enzymatic activity and binding to the cell surface.
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PMID:Chondroitin sulfate E blocks enzymatic action of heparanase and heparanase-induced cellular responses. 3158 10