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:3.1.6.12 (chondroitinase)
2,183 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Appreciable amounts of glycosaminoglycans have been found by immunocytochemistry within mature elastin fibers of human dermis. On thin sections, elastin fibers showed antigenic sites for monoclonal antibodies recognizing the unsaturated units remaining after digestion of hyaluronic acid with Streptomyces hyaluronidase and after digestion of dermatan and chondroitin sulfates with chondroitinase ABC. Moreover, sectioned elastin fibers were positive towards antibodies raised against synthetic peptides corresponding to amino acid sequences near the N-terminus of the protein core of small matrix proteoglycans PGI and PGII, respectively (Fisher et al., J. Biol. Chem. 262, 9702-9708 (1987)). This is the first demonstration that highly hydrophylic molecules are strictly associated with normally cross-linked elastin. The presence of highly hydrated molecules within the elastin polymer could greatly influence its physiological properties and behavior in pathology.
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PMID:Immunocytochemical localization of proteoglycans within normal elastin fibers. 212 20

The acid mucopolysaccharides (AMPs) in the human trabecular meshwork were studied ultrahistochemically with hyaluronidase and chondroitinase ABC digestion in 15 normal eyes and 27 cases of primary open-angle glaucoma (POAG). It was found that in normal eyes, hyaluronidase-sensitive AMPs existed in the connective tissue of cribriform meshwork and trabeculae. They could play an important role in regulating the aqueous outflow resistance. In POAG, the amount of AMPs in the trabecular meshwork was increased, leading to increased aqueous outflow resistance through the combination of hyaluronic acid with water, forming electron-dense "plaque" materials in a matrix of chondroitin sulfate.
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PMID:[An ultrahistochemical study of the trabecular meshwork in normal and open-angle glaucomatous eyes]. 214 7

Previous studies on rabbit thrombomodulin (TM) revealed that certain anticoagulant activities expressed by TM depend on the presence of an acidic domain tentatively identified as a sulfated galactosaminoglycan (Bourin, M.-C., Ohlin, A.-K., Lane, D., Stenflo, J., and Lindahl, U. (1988) J. Biol. Chem. 263, 8044-8052). The glycan was released by alkaline beta-elimination, isolated by ion-exchange chromatography, and radiolabeled by partial N-deacetylation (hydrazinolysis) followed by re-N-[3H]acetylation. The labeled product behaved like standard chondroitin sulfate on ion-exchange chromatography, exhibited a Mr of 10-12 x 10(3) on gel chromatography, and was susceptible to degradation by chondroitinase and testicular hyaluronidase. The major labeled degradation products following digestion of the glycosaminoglycan with chondroitinase were identified, depending on the incubation conditions, either as 4/6-mono-O-sulfated, 4,5-unsaturated disaccharides (delta HexA-GalNAc(S] and N-acetylgalactosamine 4,6-di-O-sulfate (GalcNAc (diS], the latter component accounting for approximately 25% of the total label, or as a major fraction of labeled trisaccharide, with the predominant structure GalNAc(diS)-GlcA-GalNAc(diS). The terminal GalNAc(diS) unit (not substituted at C3) was shown to be more susceptible to N-deacetylation during hydrazinolysis than were the internal GalNAc units (substituted at C3), and thus was more extensively labeled, resulting in over-representation of this unit. It is concluded that rabbit TM is a chondroitin sulfate proteoglycan, which carries a single glycan side chain characterized by an unusual accumulation of sulfate groups at the nonreducing terminus. Metabolically 35S-labeled TM was isolated from cultured rabbit heart endothelial cells and characterized as a chondroitin sulfate proteoglycan which accounted for 1-2% of the total 35S-labeled cell-associated macromolecules. The isolated chondroitin sulfate showed weaker antithrombin-dependent anticoagulant activity, on a molar basis, than the intact TM proteoglycan. The anticoagulant action of TM thus depends on a unique form of functional collaboration between the different constituents of a glycoconjugate.
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PMID:Isolation and characterization of the glycosaminoglycan component of rabbit thrombomodulin proteoglycan. 216 13

The role of interphotoreceptor matrix (IPM) constituents in mediating adhesion between the retina and retinal pigment epithelium (RPE) was investigated by injecting specific enzymes into rabbit eyes either intravitreally or subretinally. Retinal adhesiveness was measured by peeling the retina from the pigment epithelium 1-3 days later and observing the amount of adherent pigment. Effects of enzymes on the IPM were monitored by observation of peanut agglutinin (PNA) binding to cone matrix sheaths; retinal and RPE toxicity was excluded by electroretinography and histology. Three enzymes that degrade glycosaminoglycans or saccharides known to be constituents of the IPM (chondroitinase ABC, neuraminidase, and testicular hyaluronidase) both weakened adhesion and altered PNA binding, although the effects on the cone matrix sheaths were different for each enzyme. An enzyme specific for hyaluronic acid (Streptomyces-derived hyaluronidase), which has not been identified as a major IPM constituent, had no effect on either adhesion or PNA binding. The authors conclude that IPM-associated glycoconjugates participate in retinal adhesion, although their precise composition, interaction with IPM components, and relationship to other mechanisms of adhesion remain to be determined.
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PMID:Retinal adhesiveness is weakened by enzymatic modification of the interphotoreceptor matrix in vivo. 221 Oct 2

In order to elucidate the cytochemical properties of rat podocyte's membranes, the authors studied the constituents and distribution of glycocalyx and membrane cholesterol. Chromic-phosphotungstic acid (Cr-PTA) stain combined with enzyme digestive tests was used for the glycocalyx analysis. A digitonin fixation method was applied for the detection of membrane cholesterol. On the whole surface of podocytes, glycocalyx showed a strongly positive reaction to Cr-PTA. In normal rats, the reactivity on the urinary surface above the slit membrane of the podocyte foot processes was decreased after treatments with neuraminidase, hyaluronidase and heparitinase. The reactivity on the basal surface below the slit membrane disappeared only after treatment with chondroitinase ABC. In Puromycin Aminonucleoside nephrosis (PAN) rats, the foot processes were effaced extensively. Though a highly positive reactivity of Cr-PTA was observed on the urinary surface of the podocytes, the basal surface reacted weakly. The positive reaction of the urinary surface was not affected by the treatments with neuraminidase, hyaluronidase and heparitinase, but the weak reaction of the basal surface disappeared completely through chondroitinase ABC treatment. The distribution of membrane cholesterol was clearly revealed by the digitonin fixation method, showing digitonin cholesterol complexes of localized trilamellar structures. In normal rat podocytes the complexes were found on the urinary surface, with only a few on the basal surface. In PAN rats the complexes were seldom noticed either on the urinary or basal surfaces. The heterogeneous distribution of glycocalyx and membrane cholesterol seen in normal rat podocytes are changed remarkably under nephrotic condition.
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PMID:A cytochemical study of glycocalyx and the membrane cholesterol of rat glomerular podocytes. 226 73

The distribution of hyaluronic acid in the oocyte-cumulus complexes collected from the oviduct ampulla of superovulated hamsters was revealed by use of hyaluronidase coupled to colloidal gold. On thin sections of Lowicryl-embedded oocyte-cumulus complexes, gold particles were associated specifically with interconnecting fibrillar materials that make up the cumulus matrix. Inside the cumulus cells, gold particles were found over the cisternal membrane of the rough endoplasmic reticulum, in the contents of lysosomes and multivesicular bodies, and over Golgi vesicles of some cumulus cells. A high concentration of gold labeling was observed over the peripheral condensed chromatin and perinucleolar components in the nucleus. The cell surface of the cumulus cells also appeared to be labeled. Gold particles, however, were absent over the mitochondria and lipid vacuoles. In the oocytes, labeling was found to be associated mainly with rough endoplasmic reticulum and arrays of lamellar structures; cortical granules, mitochondria, and coated vesicles were essentially devoid of gold particles. Gold particles were also seen along the plasma membrane of the oocytes and within the perivitelline space. The zona pellucida was not labeled by hyaluronidase-gold. Different control experiments confirmed the specificity of the labeling. Digestion of thin sections with hyaluronidase prior to incubation with hyaluronidase-gold abolished the initial reaction, whereas treatment of thin sections with chondroitinase did not prevent labeling of oocyte-cumulus complexes by hyaluronidase-gold. Although the function of hyaluronic acid in the oocyte-cumulus complex at the time of ovulation and fertilization is not known, the high concentration of this particular compound in the cumulus matrix and the cumulus cells and its specific locations in the perivitelline space and in the superovulated oocytes implicate the significance of its presence and warrant future investigations.
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PMID:High-resolution localization of hyaluronic acid in the golden hamster oocyte-cumulus complex by use of a hyaluronidase-gold complex. 228 56

Previous studies have shown that bovine retinas incubated with [3H]galactose incorporated it, unmodified, into large molecules. Light and electron microscope autoradiography showed a significant proportion of the label to be in cone inner segments, and pulse-chase studies showed it was subsequently transported to the synaptic pedicles. In this report, evidence is presented to show that the galactose-labelled macromolecules are resistant to hydrolysis by proteolytic enzymes, testicular hyaluronidase, chondroitinase ABC, beta-glucosidase and beta-glucuronidase, but are readily degraded by alpha-amylase and beta-galactosidase, and to a lesser extent by beta-amylase. Treatment with alpha-amylase also leads to specific removal of radioactivity from cone inner segments and pedicles, as judged by light-microscopic autoradiography. These studies appear to indicate that the cone-specific galactose label is in glycogen or glycogen-like molecules.
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PMID:D-[3H]galactose incorporation into glycogen in retinal cone cells. 231 72

We undertook an interdisciplinary biomechanical and biochemical study to explore the extent and manner in which the total pool of proteoglycans influences the kinetic and static behavior of bovine articular cartilage in tension. Two biomechanical tests were used: (a) the viscoelastic creep test and (b) a slow constant-rate uniaxial tension test; and two enzymatic proteoglycan extraction procedures were used: (a) chondroitinase ABC treatment and (b) a sequential enzymatic treatment with chondroitinase ABC, trypsin, and Streptomyces hyaluronidase. We found that the viscoelastic creep response of all cartilage specimens may be divided into two distinct phases: an initial phase (less than 15 s), characterized by a rapid increase in strain following load application, and a late phase (15 s less than or equal to t less than 25,000 s), characterized by a more gradual increase in strain. A major finding of this study is that the kinetics of the creep response is greatly influenced by the glycosaminoglycan content of the tissue. For untreated and control specimens, the initial response comprises about 50% of the total strain, while for chondroitinase ABC and sequentially extracted specimens, the initial response comprises up to 83% of the total strain. Furthermore, most untreated and control specimens did not reach equilibrium within the 25,000 s test period, while enzymatically digested specimens often reached equilibrium in less than 100 s. Thus, we conclude that through their physical restraints on collagen, the bulk of proteoglycan present in the tissue acts to retard fibrillar reorganization and alignment under tensile loading, thereby effectively preventing sudden extension of the collagen network. In contrast, the results of our slow constant-rate uniaxial tension experiment show that essentially complete extraction of proteoglycan glycosaminoglycans does not affect the intrinsic tensile stiffness and strength of cartilage specimens or the collagen network in a significant manner. Hence, an important function of the bulk proteoglycans (i.e., the large aggregating type) in cartilage is to retard the rate of stretch and alignment when a tensile load is suddenly applied. This mechanism may be useful in protecting the cartilage collagen network during physiological situations, where sudden impact forces are imposed on a joint.
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PMID:Effects of proteoglycan extraction on the tensile behavior of articular cartilage. 232 54

This paper reports an unrecognized aspect of phosphotungstic acid staining at low pH. It provides an on-section staining method in which sialic acid-containing molecules can be demonstrated in the laminae rarae of the rat glomerular basement membrane. The staining in the basement membrane became negative after perfusion with the following cations: protamine sulphate, hexadimethrine, Alcian Blue, Ruthenium Red and Toluidine Blue. Blocking was not achieved with Alcian Blue at about pH 1. The staining was also abolished after mild methylation and demethylation restored the contrast. This is suggestive of the involvement of carboxyl groups. Prior digestion with pronase, trypsin and neuraminidase rendered the laminae rarae negative, whereas hyaluronidase, chondroitinase ABC and crude heparinase were without effect. This indicates that sialic acid groups are detected by this method and that heparan sulphate does not interfere. The staining of the epithelial plasma membrane, also carrying sialic acid groups, remained positive after neuraminidase treatment. It is presumed that this method can be applied successfully for detecting changes in the sialic acid content of the laminae rarae in rat glomerular basement membranes under normal and pathological conditions.
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PMID:Demonstration of sialic acid groups in the glomerular basement membrane of the rat with phosphotungstic acid at low pH. 241 Mar 95

Pseudocysts are unique structures found in adenoid cystic carcinomata of human salivary glands. They were studied in 13 such cases by histochemical and immunohistochemical means. The pseudocysts contained an abundance of mucoid materials which reacted strongly with both Alcian Blue and dialysed iron ferrocyanide. The mucoid material was digested with chondroitinase ABC and heparitinase, but was resistant to Streptomyces hyaluronidase. The inner surfaces of the pseudocysts were strongly reactive for laminin, whereas the interface between the tumour cell nests and the outer stromal area was intensely reactive for fibronectin. Numerous fibronectin-reactive fibrils and blood coagulation factor XIII (F-XIII)-positive cells were distributed extensively in the outer stromal area. The F-XIII-positive cells were also found within some pseudocysts. The results obtained in the present study have shown that the pseudocysts represent a peculiar structure consisting of basement membrane components; laminin, fibronectin, heparan sulphate and chondroitin sulphate.
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PMID:Histochemical studies on pseudocysts in adenoid cystic carcinoma of the human salivary gland. 241 89


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