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)

Incorporation of sulfate into alcian blue-precipitable glycosaminoglycan of 12-day-old chick embryo sterna is stimulated by addition, separately or together, of normal human serum and physiological concentrations of thyroid hormones (Audhya, T.K., and Gibson, K.D. (1975) Proc. Natl. Acad, Sci. U. S. A. 72, 604--608). We present evidence that this stimulation is due to increased synthesis of at least one proteoglycan, with minor alterations in the size and chemical composition of the glycosaminoglycans. Pulse-chase experiments showed no detectable loss of label during the chase, in control sterna or sterna incubated with serum and L-3,5,3'-triiodothyronine; thus, all incorporation was the result of synthesis of glycosaminoglycans. In double-label experiments, with 35SO4(2-) and [3H]acetate, the molar ratio of 3H and 35S incorporated into glycosaminoglycans was changed little, if at all, by addition of serum or triiodothyronine or both, at concentrations which increased incorporation up to 2-fold. Glycosaminoglycans isolated from these and other incubations gave similar elution patterns from agarose columns, and identical electrophoretic patterns on cellulose acetate. Digestion with chondroitinase ABC (chondroitin ABC lyase; EC 4.2.2.4.) showed that incorporation was into chondroitin sulfate and possibly hyaluronic acid, and that the proportions of non-sulfated, 4-sulfated, and 6-sulfated disaccharide units differed little between stimulated and unstimulated sterna. Incorporation of [3H]serine into glycosaminoglycans from papain digest of sterna paralleled incorporation of 35SO4(2-), and indicated a number average molecular weight between 21,000 and 25,000 for the newly synthesized chondroitin sulfate. This value was confirmed by gel filtration chromatography, which also showed that the average molecular weight of the newly synthesized chondroitin sulfate decreased up to 15% under conditions of 2-fold stimulation. Proteoglycans were extracted from sterna incubated with [3H]serine and 35SO4(2-) and analyzed by isopycinic centrifugation in CsCl and by zone sedimentation in a sucrose gradient. A major proteoglycan fraction could be separated by either method. Incorporation of both isotopes into this proteoglycan fraction, and into glycosaminoglycans isolated after papain digestion, was stimulated in a coordinate manner. Almost identical results were obtained with both separation techniques. The results indicate that the synthesis of the major proteoglycan, and probably also of a minor one, is stimulated by serum and triiodothyronine.
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PMID:Stimulation of proteoglycan synthesis in chick embryo sternum by serum and L-3,5,3'-triiodothyronine. 13 41

Electron microscopy of ruthenium red stained bovine aorta before and after chondroitinase digestion demonstrates proteoglycans on and between collagen fibrils. The collagen-associated proteoglycans include a proteoglycan previously purified from this tissue as demonstrated by immunocytochemistry and are extractable with high molar guanidine HC1. In loci rich in proteoglycans such as areas of turbulent flow in calves, more proteoglycan can be demonstrated morphologically, and these molecules also coat elastin.
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PMID:The ground substance of the arterial wall. Part 2. Electron-microscopic studies. 13 92

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

The sulfated proteoglycans synthesized by definitive chondroblasts in cultured 10-day chick vertebral or epiphyseal cartilages were characterized by their sedimentation profile in a sucrose gradient and their susceptibility to chondroitinase ABC (EC 4.2.2.4; chondroitin ABC lyase). These sulfated proteoglycans were indistinguishable from those synthesized by definitive chondroblasts that emerge from older cultures of somites plus notochord or in older cultures of limb buds. The sulfated proteoglycans of these definitive chondroblasts are readily distinguished from those synthesized by their mother cells, the presumptive chondroblasts, or those synthesized by dedifferentiated or bromodeoxyuridine-suppressed chondroblasts. However, the sulfated proteoglycans synthesized by presumptive chondroblasts or by dedifferentiated or bromodeoxyuridine-suppressed chondroblasts cannot be dintinguished by these techniques from those synthesized by (i) blastodisc cells, (ii) fibroblasts, (iii) spinal cord cells, or (iv) skeletal, cardiac, or smooth muscle cells. Addition of glycosaminoglycans or collagen to the medium did not induce somite or limb presumptive chondroblasts to synthesize the chondroblast-unique sulfated proteoglycans. Cells moving from the presumptive chondroblast compartment into the chondroblast compartment acquire not only the option to initiate the synthesis of chondroblast-unique collagen chains, but also the capacity to synthesize chondroblast-unique sulfated proteoglycans.
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PMID:Differences among sulfated proteoglycans synthesized in nonchondrogenic cells, presumptive chondroblasts, and chondroblasts. 13 59

Histological aspects of cervical ripening were studied on the human uterine cervix during pregnancy. Cervical specimens were taken from 25 cases of cervical laceration of primiparous women immediately after delivery, 8 primiparous women whose cervixes opened 2-3 cm, and 5 cesarean-sectioned women with unripeness of cervix. The following histochemical techniques were used: alcian blue, azure A, hyaluronidase digestion, and chondroitinase ABC digestion. The collagen bundles disintegrated into fine fibers and also underwent quantitative changes during the ripening process of the cervix. The number of connective tissue cells was increased during pregnancy, but that of mast cells was decreased. In late pregnancy, acid mucopolysaccharides in the cervical ground substance were found to increase.
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PMID:Histological aspects of cervical ripening. 13 67

After chondroitinase digestion of bovine nasal and tracheal cartilage proteoglycans, subsequent treatment with trypsin or trypsin followed by chymotrypsin yielded two major types of polypeptide-glycosaminoglycan fragments which could be separated by Sepharose 6B chromatography. One fragment, located close to the hyaluronic acid-binding region of the protein core, had a high relative keratan sulfate content. This fragment contained about 60% of the total keratan sulfate, but less than 10% of the total chondroitin sulfate present in the original proteoglycan preparation. The weight average molecular weight of the keratan sulfate-enriched fragment was 122,000, as determined by sedimentation equilibrium centrifugation. The chemical and physical data indicate that this fragment contains an average of 10 to 15 keratan sulfate chains, if the average molecular weight of individual chains is assumed to be about 8,000, and about 5 chondroitin sulfate chains attached to a peptide of about 20,000 daltons. The other population of fragments was derived from the other end of the proteoglycan molecule, the chondroitin sulfate-enriched region, and contained mainly chondroitin sulfate chains. About 90% of the total chondroitin sulfate, but only 20 to 30% of the total keratan sulfate was recovered in these fragments. On the average, approximately 5 chondroitin sulfate chains and 1 keratan sulfate chain could be linked to the same peptide. Another 10 to 20% of the total keratan sulfate, originally found in or near the hyaluronic acid-binding region, was not separated from the chondroitin sulfate-enriched fragments. Hydroxylamine could be used to liberate a large molecular size, chondroitin sulfate-enriched fragment (Kav 0.54 on Sepharose 2B) from the proteoglycan aggregates. The remainder of the protein core, containing the keratan sulfate-enriched region, was bound to hyaluronic acid with the link proteins and recovered in the void volume on the Sepharose 2B column.
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PMID:Distribution of keratan sulfate in cartilage proteoglycans. 13 6

13C nmr spectral parameters were measured for intact bovine nasal cartilage tissue, the purified proteoglycan aggregate, and chondroitin 4-sulfate. A comparison of integrated intensities obtained for four different samples of fresh tissue with an ethylene glycol standard indicated that at least 80% of the total glycosaminoglycan carbons in the tissue contributed to the spectrum. This result was confirmed by intensity measurements obtained at 56 degrees on fresh tissue and at 37 degrees after extensive papain digestion of fresh tissue. Spin lattice relaxation times and nuclear Overhauser enhancements were analyzed in terms of the following models of molecular motion: (a) single correlation time; (b) log X2 distribution of correlation times; and (c) anisotropic motion. The analysis indicates that the segmental motions of glycosaminoglycan chains are characterized by a broad distribution of correlation times centered at about 50 ns. Slow motion contributions to glycosaminoglycan line widths were reduced by dipolar decoupling (gammaH2/2pi = 65 kHz). Collagen intensity was observed in dipolar decoupled spectra, but not in scalar decoupled spectra of intact tissue, showing that the type II collagen in cartilage undergoes anisotropic motion like the type I collagen in tendon. Only glycosaminoglycan resonances were observed in spectra of a solution of proteoglycan aggregate before and after chondroitinase digestion. After subsequent digestion with papain, protein resonances were observed. These results suggest that the protein portions of the proteoglycan aggregate structure, in contrast with the glycosaminoglycan chains, have restricted backbone mobility and consequently a defined backbone structure.
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PMID:Investigation of molecular motion of proteoglycans in cartilage by 13C magnetic resonance. 14 Aug 75

Rat liver cells grown in primary cultures in the presence of [(35)S]sulphate synthesize a labelled heparan sulphate-like glycosaminoglycan. The characterization of the polysaccharide as heparan sulphate is based on its resistance to digestion with chondroitinase ABC or hyaluronidase and its susceptibility to HNO(2) treatment. The sulphate groups (including sulphamino and ester sulphate groups) are distributed along the polymer in the characteristic block fashion. In (3)H-labelled heparan sulphate, isolated after incubation of the cells with [(3)H]galactose, 40% of the radioactive uronic acid units are l-iduronic acid, the remainder being d-glucuronic acid. The location of heparan sulphate at the rat liver cell surface is demonstrated; part of the labelled polysaccharide can be removed from the cells by mild treatment with trypsin or heparitinase. Further, a purified plasma-membrane fraction isolated from rats previously injected with [(35)S]sulphate contains radioactively labelled heparan sulphate. A proteoglycan macromolecule composed of heparan sulphate chains attached to a protein core can be solubilized from the membrane fraction by extraction with 6m-guanidinium chloride. The proteoglycan structure is degraded by treatment with papain, Pronase or alkali. The production of heparan [(35)S]sulphate by rat liver cells incubated in the presence of [(35)S]sulphate was followed. Initially the amount of labelled polysaccharide increased with increasing incubation time. However, after 10h of incubation a steady state was reached where biosynthetic and degradative processes were in balance.
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PMID:Structure and metabolism of rat liver heparan sulphate. 14 28

Proteoglycans were extracted from bovine articular cartilage with guanidine-HCl and fractionated in cesium chloride density gradients by equilibrium ultracentrifugation. The acidic glycosaminoglycan (AGAG) components were then determined enzymatically with chondroitinase-ABC and streptomyces hyaluronidase. Under associative and dissociative conditions, the distribution of the AGAG components was as follows: the ratio of 4-sulfated disaccharide units to total AGAG increased with decreasing density gradients whereas that of 6-sulfated disaccharide units to total AGAG increased with increasing density gradients. The ratio of disulfated disaccharide units to total AGAG increased somewhat with decreasing density gradients whereas that of non-sulfated disaccharide units tended to decrease. Although the cartilage proteoglycan macromolecules were heterogeneous, a certain regularity was observed with respect to the distribution of sulfate and the degree of sulfation in the chondroitin sulfate chains of the proteoglycans.
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PMID:Constitutional heterogeneity of the glycosaminoglycans in articular cartilage proteoglycans. 14 4

Medullary tissue of the normal rat kidney was perfused with 3 percent glutaraldehyde (GA), incubated in 0.5 percent cetyl pyridinium chloride and postfixed in 1 percent OsO4. In comparison with the ordinary fixation with GA and OSO4, the medullary interstitium represented abundant matrical substance that is rich in acid mucopolysaccharides (AMPS) and morphologically represents a diffuse reticular structure consisting of 30 to 150 a thick microfibrils and granular structures of 300 to 500 A in diameter. When chondroitinase was applied before OsO4 treatment, the dense granes disappeared and the microfibrils were replaced by loosely textured 30 A thick microfilaments. After hyaluronidase treatment the microfibrils disappeared and most granules changed into a ring-shaped structure with an electronlucent central portion. These results suggest that the reticular structure consists of microfilaments of hyaluronates and amorphous masking substance of chondroitin sulfates. In the dense granule, hyaluronates become concentrated in the central portion and chondroitin sulfate in the peripheral zone. When perfused with a CPC-containing GA, the medullary interstitium was diffusely filled with a large amount of fine granular substances suggesting the presence of water soluble free AMPS filling the reticular space.
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PMID:Ultrastructure and histochemistry of the medullary interstitial matrix of rat kidney. 14 5


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