Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Proteoglycans of bovine compact bone were purified by chromatography of the formic acid precipitate of an EDTA extract. The sequential chromatographic steps consisted of gel filtration on Sepharose CL-6B in 4-M guanidine HCl, ion-exchange chromatography on DEAE-Sephacel in 4-M urea and rechromatography on Sepharose CL-6B in 4-M guanidine HCl. The preparation consisted of a relatively small proteoglycan (Kav = 0.4 on Sepharose CL-6B) containing about 40% protein, 21% hexuronic acid, 23% galactosamine and lesser amounts of other monosaccharides. The core protein was shown by gradient NaDodSO4 gel electrophoresis, electrotransfer and immunodetection to be monodispersed with an Mr = 45,000. Analysis of glycopeptides obtained after papain digestion of the proteoglycan and separation from glycosaminoglycan chains by gel chromatography, indicated that both N-linked and O-linked oligosaccharides were present. The glycosaminoglycan chains liberated by papain digestion eluted from Sepharose CL-6B as a broad peak with Kav = 0.50, slightly ahead of the position of elution of bovine nasal cartilage glycosaminoglycans (Kav = 0.52); the bone glycosaminoglycans are thus slightly larger than those from cartilage and smaller than the ones attached to fetal bone proteoglycans. These chains were totally susceptible to chondroitinase AC II, a procedure that yielded unsaturated disaccharides corresponding predominantly to chondroitin-4-sulfate, and to a lesser extent chondroitin-6-sulfate. Antisera raised against adult bone proteoglycans cross-reacted with core protein of bone proteoglycan (obtained after chondroitinase digestion) but not with papain digested proteoglycan. In addition, they cross-reacted with core protein and trypsin-liberated, chondroitin sulfate rich region (AlTAl) derived from cartilage proteoglycans and, to a lesser extent, rat bone proteoglycans. No cross-reactivity could be detected to Smith-degraded cartilage proteoglycans, bone acidic glycoproteins or serum proteins.
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PMID:Proteoglycans of adult bovine compact bone. 293 15

The mineral deposits in rabbit articular cartilage induced by intra-articular injections of glucocorticoid were studied by light and electron microscopy, using histochemical techniques and x-ray-probe microanalysis. This study demonstrated that the mineral deposits consisted of hydroxyapatite crystals. The initial deposition of hydroxyapatite crystals was seen around degenerating chondrocytes, where a halo-like pericellular space contained a large amount of electron-dense amorphous material. The initial precipitation of the crystals with a low ratio of calcium to phosphorus and the subsequent growth of crystals were seen only on or within the electron-dense amorphous material until the crystals formed mature, calcified nodules. The electron-dense amorphous material frequently coexisted with proteoglycans and degenerated collagen fibers. Digestion studies using chondroitinase ABC, papain, or chloroform and methanol suggested that the electron-dense amorphous material consisted of some protein and a small amount of lipid. Matrix vesicles were rarely seen in the calcifying areas. In addition, there was a correlation between sulphur, calcium, and phosphorus in the calcifying areas, where the relative element concentrations were: S (estimation counts of sulphur) = -0.862 X (calcium counts) + 1.472 X (phosphorus counts) + 102.146. This study demonstrated that electron-dense amorphous material, proteoglycans, and degenerated collagen fibers are present in loci where the hydroxyapatite crystals are formed in articular cartilage.
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PMID:Hydroxyapatite deposition in articular cartilage by intra-articular injections of methylprednisolone. A histological, ultrastructural, and x-ray-microprobe analysis in rabbits. 300 26

Recently, we described a bovine aortic phosphatase which we called PCM-phosphatase (polycation modulable) because its activity in vitro can be modulated by polycations such as polylysine and histone-H1 (Di Salvo J, Gifford D, Kokkinakis A. Modulation of aortic protein phosphatase activity by polylysine. Proc Soc Exp Biol Med 177:24-32, 1984). We We suspected that polycationic modulation might be inhibited by polyanionic glycosaminoglycans. Accordingly, an aortic anionic substance was purified by sequential steps including (a) heating aortic extracts at 90 degrees C, (b) precipitation of protein with (NH4)2 SO4, and (c) anionic-exchange chromatography on a Mono Q HR 5/5 column using the Pharmacia fast protein liquid chromatography system. Electrophoresis (polyacrylamide-agarose) of the purified substance revealed one band which stained metachromatically with toluidine blue; however, no staining occurred with Coomassie blue. Electrophoretic mobility increased following proteolytic digestion of the substance with papain. The substance produced concentration-dependent reversal of polylysine-mediated inhibition of myosin light chain dephosphorylation, and it also reversed polylysine-mediated stimulation of phosphorylase phosphatase activity expressed by PCM-phosphatase. Its ability to inhibit or reverse polycationic modulation was abolished after incubation with either chondroitinase AC or chondroitinase ABC. Based on these properties the substance was identified as a chondroitin proteoglycan. Commercially available glycosaminoglycans (heparin and chondroitin sulfates) also reversed polycationic modulation. The results show that modulation of phosphatase activity may be significantly modified by naturally occurring glycosaminoglycans. These studies may also have an important bearing on the purported roles of phosphatase(s) and glycosaminoglycans in calcification of soft tissues.
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PMID:Glycosaminoglycans and a newly purified aortic chondroitin proteoglycan block polycationic modulation of protein phosphatase activity. 302 91

A Fisher rat thyroid cell line was maintained in culture and the cells were labeled with [3H]glucosamine, [35S]sulfate, and [35S]cysteine to examine the synthesis of proteoglycans. 3H and 35S radioactivity from these precursors were incorporated into both chondroitin sulfate (CS) and heparan sulfate (HS) proteoglycans. CS proteoglycans were almost exclusively secreted into the medium while HS proteoglycans remained mainly associated with the cell layer. Single chain glycosaminoglycans released by papain digestion or alkaline borohydride treatment of either the CS or HS proteoglycans had average molecular weights of approximately 30,000 on Sepharose CL-6B chromatography. Both CS and HS proteoglycans were relatively small and contained only one or two glycosaminoglycans chains. 3H and 35S incorporation into both CS and HS proteoglycans were increased by thyroid-stimulating hormone (TSH) in a dose-dependent manner, which is in part explained by an adenylate cyclase-dependent mechanism as indicated by a similar effect in response to dibutyryl cAMP. TSH enhanced the incorporation of 35S into CS from [35S]cysteine about 1.5-fold and that from [35S]sulfate about 2-fold. This result demonstrated that the increased 35S incorporation from the [35S]sulfate precursor reflects an actual increase in sulfate incorporation and is not simply a result from an apparent increase in specific activity of the phosphoadenosine phosphosulfate donor. Analysis of disaccharides from chondroitinase digests revealed that the proportion of non-sulfated, 4-sulfated, and 6-sulfated disaccharides was not altered appreciably by TSH. These results, together with the disproportionate increase in 3H incorporation into CS from [3H]glucosamine, indicated that TSH increased the specific activity of the 3H label as well. Chase experiments revealed that CS proteoglycans were rapidly (t1/2 = 15 min) secreted into the medium and that the degradation of cell-associated proteoglycans was enhanced by TSH.
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PMID:Characterization of proteoglycans synthesized by rat thyroid cells in culture and their response to thyroid-stimulating hormone. 312 76

Nonsulfated, monosulfated, and disulfated glycopeptides containing the entire carbohydrate sequence of the glycosaminoglycan-specific linkage region were isolated after exhaustive enzymatic digestions of Swarm rat chondrosarcoma proteoglycans with chondroitinase ABC, papain, and Pronase. Their structures were examined by 500 MHz 1H NMR spectroscopy. The nonsulfated compound has the following structure with trace amounts of a few additional amino acids: delta 4,5-GlcA beta 1-3GalNAc beta 1-4GlcA beta 1-3Gal beta 1-3Gal beta 1-4Xyl beta 1-O-Ser. The monosulfated compound has an ester sulfate on C-4 of the GalNAc residue and the disulfated compound has an additional hitherto unrecognized ester sulfate on C-4 of the second galactose residue which is remote from the innermost xylose. This new structure was confirmed by two-dimensional homonuclear Hartmann-Hahn spectroscopy. The molar ratio of the isolated nonsulfated, monosulfated, and disulfated compounds was 53:37:10 based on the serine contents. Biological significance of the newly found sulfated linkage structure is discussed.
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PMID:Structural studies on sulfated glycopeptides from the carbohydrate-protein linkage region of chondroitin 4-sulfate proteoglycans of swarm rat chondrosarcoma. Demonstration of the structure Gal(4-O-sulfate)beta 1-3Gal beta 1-4XYL beta 1-O-Ser. 313 45

Proteodermatan sulfate was isolated from the skin of human, female breast in 6-M urea and proteolytic inhibitors at 70 degrees C and purified on Sephacryl S-200. It was composed of 55% protein and 45% dermatan sulfate, displayed one protein and carbohydrate-stainable band on agarose-polyacrylamide gels, yielded dermatan sulfate after digestion by papain, and its calculated E0.1% 1 cm, 280 nm was 16.2. Its mucopolysaccharide portion was digested by chondroitinase ABC but not by chondroitinase AC. This proteoglycan was used to immunize rabbits. Double diffusion of antiserum against the antigen or its core protein resulted in one precipitation band. Antiserum did not cross-react with bovine collagen type I, human fibronectin, dermatan sulfate, hyaluronic acid, heparin, heparan sulfate or the chondroitin sulfates by double diffusion. The antiserum titer determined by radioimmunoassay was 1:16,000. This assay was not affected by a 40-fold excess of dermatan sulfate. Purified IgG molecules were apparently associated with collagen in human breast mid-dermis as demonstrated by indirect immunoelectron microscopy with ferritin-labeled goat antirabbit IgG. The results indicate that rabbit anti-human, anti-proteodermatan sulfate IgG is highly specific for the core protein of dermatan sulfate and confirm the hypothesis that in vivo proteodermatan sulfate is closely associated with collagen.
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PMID:Immunoelectron microscopy of proteodermatan sulfate in human mid-dermis. 315 40

The synthesis of extracellular [35S]-SO4- and [3H]-glucosamine-labelled glycosaminoglycan (GAG) was studied in confluent human gingival fibroblast cultures in vitro. The differential synthesis of the total chondroitin sulphate/dermatan sulphate (CS/DS) and heparan-sulphate (HS) fraction was measured following chondroitinase-ABC digestion, nitrous-acid treatment and column chromatography on Sephadex G50. Control cultures synthesized a CS/DS fraction that represented 78 per cent of the total [35S]-SO4-GAG; the residual 22 per cent was heparan sulphate. Similar cultures were labelled with [3H]-glucosamine and the proportions of a high molecular-weight hyaluronic acid (HA) and proteoglycan fractions measured by gel-filtration HPLC after papain and hyaluronidase digestions. The HA fraction represented 66 per cent of the total isotope incorporated in control cultures. GAG chains released on treatment with papain (24 per cent of the total label incorporated) were of apparent molecular weight 17-20 kDa. All cultures exposed to Bacteroides gingivalis W50 outer membrane at concentrations between 2 and 50 micrograms ml-1 displayed a decrease in the CS/DS fraction and a reciprocal increase in the HS. However, the proportion of HA synthesized was slightly enhanced with a reciprocal decrease in the proteoglycan (papain-digestible) fraction. There was no alteration in the molecular weight of the papain-digestion products or the size distribution of the hyaluronic-acid fraction.
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PMID:The effect of the outer membrane fraction of Bacteroides gingivalis W50 on glycosaminoglycan metabolism by human gingival fibroblasts in culture. 325 24

The synthesis of proteoglycans by aorta explants from rabbits with diet-induced atherosclerosis and controls was studied by 35S-incorporation. Proteoglycans were isolated under dissociative conditions from incubation medium and from arterial explants. Additionally, the tissue proteoglycans that were not extracted by 4 M guanidine-HCl were solubilized by digestion of the tissue by elastase in the presence of proteinase inhibitors. The residual tissue was hydrolyzed by papain and glycosaminoglycans were isolated. The atherosclerotic aorta tissue incorporated twice the amount of 35S into proteoglycans than observed for controls; in both groups about 70% of the label incorporated into the tissue was noted in the proteoglycans extracted by guanidine-HC;, while about 30% of the total 35S-labeled proteoglycans synthesized by the explants were found in the media. Atherosclerotic tissue incorporated 35S predominantly into chondroitin sulfate proteoglycans when compared to control tissue. The chondroitinase ABC-digestable proteoglycans that were extracted by guanidine-HCl from atherosclerotic tissues were of larger molecular size than those from control tissue, but the core proteins from these preparations were similar. The heparan sulfate proteoglycan that was obtained by dissociative extraction from atherosclerotic tissue had greater amounts of N-acetyl and lesser amounts of N-sulfate ester groups than the preparation from control tissue. Digestion of the tissue by elastase yielded heparan sulfate proteoglycan as the major constituent in both groups, although atherosclerotic tissue contained relatively small amounts of this proteoglycan. The residual tissue from both groups contained chondroitin sulfate and heparan sulfate as the major glycosaminoglycans with the latter showing a decrease with atherosclerosis. Atherosclerotic tissue secreted into the medium about two-fold more 35S-labeled proteoglycans with larger molecular size than control tissue; proteoglycans of the heparan sulfate and chondroitin sulfate types were the major constituents in the culture medium of both tissues. Thus, proteoglycans undergo both quantitative and qualitative changes in atherosclerosis, reflecting the enhanced smooth muscle cell activity. These changes are potentially important in modulating lipoprotein binding and hemostatic properties, as well as fibrillogenesis of the arterial wall.
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PMID:Composition of proteoglycans synthesized by rabbit aortic explants in culture and the effect of experimental atherosclerosis. 334 58

Although the core protein of a heparan sulfate proteoglycan has been detected in brain microvessel basement membranes by immunoperoxidase staining, cytochemical evidence of a glycosaminoglycan component, in the form of discrete staining with ruthenium red, is not found. To resolve this discrepancy, we examined the glycosaminoglycan content of this basement membrane directly. Microvessels were isolated from pig cerebral cortex, and basement membranes freed from cellular elements. Following digestion with papain and Pronase, the glycosaminoglycans were precipitated with cetyl pyridinium chloride and ethanol. The resulting extract contained uronic acid, and after electrophoresis on Super Sepraphore revealed 2 bands: One co-migrated with heparan sulfate standard, the other with chondroitin sulfate A and C. The first was completely eliminated by nitrous acid and heparitinase, but not by hyaluronidase or chondroitinase ABC and was therefore confirmed as heparan sulfate; the other band was eliminated by chondroitinase ABC but not by the other three treatments. The findings suggest that basement membrane of brain microvessels, like other vascular basement membranes, contains heparan sulfate and chondroitin sulfate A and/or C. The failure of staining with ruthenium red is probably a result of unique structural features of this basement membrane, rather than an absence of glycosaminoglycan.
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PMID:Isolation of glycosaminoglycans from basement membranes of brain microvessels. 334 40

Our previous work showed that vitamin C deficiency caused about a 70-80% decrease in the incorporation of [35S]sulfate into proteoglycan of guinea pig costal cartilage, coordinately with a decrease in collagen synthesis (Bird, T. A., Spanheimer, R. G., and Peterkofsky, B. (1986) Arch. Biochem. Biophys. 246, 42-51). We examined the mechanism for decreased proteoglycan synthesis by labeling normal and scorbutic cartilage in vitro with radioactive precursors. Proteoglycan monomers from scorbutic tissue were of a slightly smaller average hydrodynamic size than normal but there was no difference in the size of the glycosaminoglycan chains isolated after papain digestion. The type of glycosaminoglycans synthesized and the degree of sulfation were unaffected as determined by chondroitinase ABC digestion and duel labeling with [35S]sulfate and [3H]glucosamine. Conversion of [3H]glucosamine to [3H]galactosamine also was unimpaired. There was about a 40% decrease in core protein synthesis, measured by [14C]serine incorporation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Nevertheless, decreased incorporation of [35S]sulfate into scorbutic tissue persisted in the presence of p-nitrophenyl-beta-D-xyloside and cycloheximide, which indicated that the site of the scorbutic defect was beyond core protein synthesis and xylosylation. Galactosyltransferase activity in scorbutic cartilage decreased to about one-third the levels in control samples in parallel with the decreases in proteoglycan and collagen synthesis. Our results suggest that the step catalyzed by this enzyme activity, the addition of galactose to xylose prior to chondroitin sulfate chain elongation, is the major site of the scorbutic defect in proteoglycan synthesis. Decreased enzyme activity may be related to increased cortisol levels in scorbutic serum.
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PMID:Mechanism for the decreased biosynthesis of cartilage proteoglycan in the scorbutic guinea pig. 373 50


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