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)

35S- as well as 3H-labeled glycosaminoglycans (GAG) produced by cultivated epithelium and fibroblasts of the rabbit cornea were treated with testicular hyaluronidase, leech hyaluronidase and chondroitinase-ABC or -AC. The fractionation-patterns of enzyme-treated GAG were compared with blanks not exposed to enzymes. The epithelial GAG revealed to be generally more resistant to the enzymatic degradation than the GAG synthesized by the fibroblasts, but--depending on the enzyme--in the GAG of both cell types the same fractions were attacked. The decline of the radioactivity in the fractions of enzyme-treated GAG allows the conclusions that both cell types produce relatively small amount of keratan sulfate but mainly chondroitin sulfates with a different degree of sulfation. In addition GAG, not present in the normal cornea, are synthesized: hyaluronic acid chiefly by fibroblasts and probably dermatan sulfate. The possible role of the fibroblastic and epithelial GAG in corneal wound repair is discussed.
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PMID:Biosynthesis of glycosaminoglycans by mammalian corneal epithelium and fibroblasts in vitro. II. Approach to specify the GAG from the two cell types. 12 25

The extracellular sulfated glycosaminoglycans synthesized by explants of rabbit cornea and sclera, and by confluent cultures of corneal fibroblasts after incubation in medium containing 35S-sulfate were compared. The glycosaminoglycans isolated from corneal explants differed considerably from those obtained from confluent corneal fibroblast cultures and scleral explants. Only the corneal explants secreted into the nutrient medium a population of enzyme-resistant 35S-sulfate-labeled glycosaminoglycan that eluted from Dowex 1-X2 (Cl-) at a 3 M sodium chloride concentration, and which was resistant to testicular hyaluronidase, chondroitinase ABC, and nitrous acid degradation. With time, corneal explants gradually synthesized less of this fraction with these attributes of keratosulfate. If the corneal epithelium and endothelium remained on the corneal explants the total incorporated 35S-sulfate was approximately double that obtained when the cornea was striped of these cells.
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PMID:A comparative study of extracellular sulfated glycosaminoglycans synthesized by rabbit corneal fibroblasts in organ and confluent cultures. 13 75

Isolated, purified small chondroitin (dermatan) sulphate proteoglycans from corneas of cow and rabbit and cow sclera were stained with Cupromeronic blue in 'model' experiments. The lengths and thicknesses of the images were compared with those of the same proteoglycans stained in the tissue, using the critical electrolyte concentration principle to give specificity for sulphated proteoglycans, and keratanase 1 or chondroitinase ABC digestion to distinguish between chondroitin and keratan sulphate. Corrections for orientation of the stained glycan filaments within the section plane were made to convert the observed lengths to true average lengths. Observed lengths of stained chondroitin (dermatan) sulphate were greater than those of keratan sulphate, both in models and tissues, in agreement with published data from biochemical and rotary-shadowing studies, in both species. Corrected (true) average lengths of stained isolated chondroitin (dermatan) sulphate proteoglycans were slightly, but not significantly, longer than expected from rotary shadowing or biochemical measurements. Keratan sulphate lengths were similarly somewhat longer. The data support the idea that Cupromeronic blue acts as a scaffold that helps maintain polyanion shape against distortion on staining. Stained filaments in tissues were sometimes over twice the length of isolated stained proteoglycans, suggesting that 2 glycan chains were aligned end-to-end. Thicknesses of proteoglycan filaments suggested that at least 2 glycan chains were aligned side-by-side, both in models and in tissues. A scheme for proteoglycan tertiary structure in cornea is proposed, in which glycan chains may bridge collagen fibrils in duplexed forms similar to those observed in rotary shadowed preparations.
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PMID:Morphometry of cupromeronic blue-stained proteoglycan molecules in animal corneas, versus that of purified proteoglycans stained in vitro, implies that tertiary structures contribute to corneal ultrastructure. 145 71

To study differences in the distribution of proteoglycans and their relationships to collagen fibrils in the cornea and sclera, bovine cornea and sclera were examined histochemically using the ruthenium red (RR) staining method. RR-positive granules (30 nm in diameter) were present in association with fine filamentous materials (3 nm in diameter and 30-100 nm in length) in the interfascicular spaces of collagen bundles in both the corneal stroma and sclera. The amount of these materials was smaller in the sclera than in the cornea. The characteristic band-like arrangement of RR-positive granules connected by filamentous materials at intervals of 80-100 nm was found only in the cornea. In enzyme digestion experiments, tissue sections were treated by chondroitinase ABC, AC, and keratanase before RR staining. The RR-positive granules and their associated filamentous materials were darkly stained after chondroitinase AC or keratanase digestion, but displayed markedly lighter staining after chondroitinase ABC digestion. These results indicate that RR-positive granules and filamentous materials contain dermatan sulfate proteoglycan.
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PMID:Electron microscopic study of distribution of proteoglycans in bovine cornea and sclera. 177 92

Chick embryonic skeletal muscle synthesizes three major types of proteoglycans: large chondroitin sulfate proteoglycans, small dermatan sulfate proteoglycans and small heparan sulfate proteoglycans. A monoclonal antibody has been raised which recognizes the small dermatan sulfate proteoglycan. Immunoblot analysis of a partially purified preparation of skeletal muscle proteoglycans indicates that the antibody reacts with a molecule which migrates with an estimated Mr of 100,000. Prior treatment of the proteoglycans with chondroitinase results in immunostaining of a species of estimated Mr 45,000. These values for the intact proteoglycan and its core protein suggest that the antibody is directed against a proteoglycan of the PG-II or decorin class. Immunohistochemistry indicates a widespread distribution of the proteoglycan, which is localized in connective tissue septa of skeletal and cardiac muscle, dermis, tendon, bone, perichondrium and cornea. Immunoblot analysis of the proteoglycan core proteins from these tissues demonstrates that the antibody recognizes the same 45,000-dalton band in each tissue. The widespread tissue distribution is also consistent with the antibody being directed against an epitope of PG-II. Neither the glycosaminoglycan chains nor N-linked oligosaccharides are required for reactivity and the antibody cross-reacts with other avian material, but not mammalian. This antibody, which has been designated CB-1, reveals developmental stage-specific changes in the deposition of PG-II in embryonic limb bud and skeletal muscle.
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PMID:Generation of a monoclonal antibody against avian small dermatan sulfate proteoglycan: immunolocalization and tissue distribution of PG-II (decorin) in embryonic tissues. 178 33

A 68-year-old man and a 66-year-old woman had diffuse corneal stromal deposits that stained with alcian blue and colloidal iron but did not react with periodic acid-Schiff stain and lipid stains. Similar deposits were found within postmortem sclera in one case, but not in other ocular or extraocular tissues. The abnormal material was sensitive to testicular hyaluronidase and chondroitinase. The material reacted with monoclonal antibody 9-A-2 after digestion by chondroitinase AC in one case and ABC in both cases, which is consistent with the identification of the glycosaminoglycans chondroitin 4-sulfate and dermatan sulfate. Electron microscopic examination of the cornea in both cases disclosed granular material in vacuoles dispersed extracellularly and, rarely, in keratocytes. Results of blood and skin fibroblast enzyme assays for clinically relevant mucopolysaccharidoses and mucolipidoses were normal in both patients, and there were no somatic abnormalities suggesting a storage disease.
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PMID:Unusual mucopolysaccharide disorder with corneal and scleral involvement. 211 Apr 15

Ultrastructural localization of proteoglycans (PGs) in 1-week- to 2-year-old scar was determined by staining with cuprolinic blue dye (CBD) after specific enzymatic digestion of keratan sulfate (KS) glycosaminoglycans (GAGs) or chondroitin sulfate glycosaminoglycans (CSs). High critical electrolyte conditions were maintained for CBD-staining, specific for high-sulfated GAGs. Although KS was detected in the 1-week-old wound, no CBD-stained KS was seen in the anterior stroma adjacent to the wound. The CS was present throughout the 1-week-old wound and adjacent stroma, and PGs were biosynthetically 35SO4-labeled in normal stroma. Subsequently, radioactivity from labeled PGs in normal stroma adjacent to the wound moved into scar tissue during healing. Marked sensitivity of PGs to Chondroitinase ABC indicated an abundance of CS in 2-week-old scars. Punctate CBD-staining and immunohistochemical evidence suggested chemically altered KS is present in the 2-week-old anterior scar. The pattern of CBD-staining in 1- and 2-week scars, after chondroitinase treatment, suggested KS in the younger scar is similar to adult high-sulfated GAG, whereas KS in the 2-week scar contains primarily newly synthesized low-sulfated KS. The latter is consistent with previous immunochemical and biochemical analyses. Cytochemical and immunohistochemical evidence indicated that KS is not present in the 2-week-old posterior scar. By the week 8 of healing, CBD-stained KS was present throughout most of the scar, except along the posterior margin, consistent with earlier stages of healing. The CBD-stained structures in the first 8 weeks of healing were reminiscent of stained GAGs in normal developing cornea. This fetal-like CBD-staining pattern seen in scar, however, changed to that of the normal adult by the 2nd year of healing. The significance of these observations relate to our contention that healing adult cornea recapitulates some ontogenetic events of the normal cornea, and that the nonuniform distribution and chemical properties of GAGs in scar tissue are a function of the movement of existing proteoglycans and de novo synthesis of altered macromolecules.
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PMID:Morphologic analyses of proteoglycans in rabbit corneal scars. 212 Jan 45

Corneal buttons were obtained from patients with types 1 and 2 macular corneal dystrophy (MCD) and from control patients with Fuchs' dystrophy or keratoconus. Buttons were incubated for 20 h in the presence of [3H]glucosamine or [2-3H]mannose. Radiolabeled proteoglycans and lactosaminoglycan-glycoproteins (L-GPs) were purified using chromatography on Q-Sepharose, Superose 6, and octyl-Sepharose. They were identified using chondroitinase ABC, keratanase or endo-beta-galactosidase digestion, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis or Superose 6 chromatography. This study confirms previous reports that type 1 MCD corneas synthesize a normal dermatan sulfate-proteoglycan (DS-PG) and an abnormal keratan sulfate-proteoglycan (KS-PG). The data indicate that typ 1 MCD corneas synthesize L-GP instead of KS-PG. This L-GP has a core protein of similar hydrophobicity (elution from octyl-Sepharose) and nearly similar mass (42 kDa) as the core protein of the KS-PG. It has identical glycoconjugates as those of the KS-PG except that they lack sulfate. Thus, type 1 MCD fails to synthesize keratan sulfate as a result of a defect in a sulfotransferase specific for sulfating lactosaminoglycans. Further, proteoglycans synthesized by a cornea from a patient with type 2 MCD were studied. This cornea synthesized a normal ratio of KS-PG to DS-PG although net synthesis of proteoglycans was approximately 30% below normal. The KS-PG appeared normal whereas the DS-PG had dermatan sulfate chains that were approximately 40% shorter than normal.
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PMID:Proteoglycan biosynthesis by human corneas from patients with types 1 and 2 macular corneal dystrophy. 239 54

The capacity of various blood-borne cells, whether normal or malignant, to extravasate was found to correlate with heparanase-mediated degradation of HS in subendothelial ECM. This degradation was stimulated by proteases or plasminogen and inhibited by native heparin and by various modified nonanticoagulant species of heparin. These heparins also induced a marked reduction in tumor cell metastasis and autoimmune diseases in experimental animals. Heparanase-mediated degradation of HS in ECM also released EC growth factors that are stored in ECM, most likely by high affinity binding to HS. Such growth factors were extracted from subendothelial ECM synthesized in vitro and from basement membranes of the cornea in vivo, and are structurally and functionally related to bFGF;bFGF binds to ECM and is readily released by incubation with either HS, heparin or low MW heparin fragments as well as by various normal and malignant cells and by heparanase-mediated degradation of ECM HS. In contrast, there was little or no release of growth-promoting activity upon incubation of ECM with hyaluronic acid, chondroitin sulfate or chondroitinase ABC. A model is proposed suggesting that regulation of capillary growth and neovascular response may result from displacement of an angiogenic protein (bFGF) from its storage sites within basement membranes.
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PMID:Involvement of heparanase in tumor metastasis and angiogenesis. 246 49

35S-Labeled proteoglycans produced by chondrocytes from immature and mature rabbits were fractionated on associative CsCl gradients. In all cultures, greater than 85% of the incorporated radioactivity was present in the A1 fraction (rho 1.60) as chondroitin sulfate/keratin sulfate-substituted aggregating proteoglycan monomer; the remainder was present in small proteoglycans in the A2, A3, and A4 fractions of low buoyant densities (rho 1.53, 1.45, 1.37, respectively). Detailed glycosaminoglycan analysis of the A2, A3, and A4 fractions showed dermatan sulfate-rich species were present throughout. However, in both immature and mature cultures, 30-45% of the glycosaminoglycans in the A3/A4 combined fractions were present as keratan sulfate, as shown by insensitivity to digestion with chondroitinase ABC, specific digestion with endo-beta-galactosidase, and reactivity with antibody 5D4. Immature and mature chondrocytes synthesized very similar amounts of the low buoyant density keratan sulfate proteoglycan on a per cell basis. Moreover, 51 and 37% of the total keratan sulfate produced by immature and mature chondrocytes, respectively, were present in the low buoyant density proteoglycan. Pulse-chase experiments indicated that the low buoyant density keratan sulfate was not derived from the large aggregating proteoglycan by proteolysis in the extracellular space. The small keratan sulfate proteoglycans appear to be present as a species distinct from the small dermatan sulfate proteoglycans in these cultures in that they can be separated on Q-Sepharose chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The apparent size (40-60 kDa), composition, and heterogeneity of the keratan sulfate proteoglycans suggest that they may be related to the small keratan sulfate proteoglycans of cornea.
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PMID:Synthesis of small proteoglycans substituted with keratan sulfate by rabbit articular chondrocytes. 252 36


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