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Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cultured bovine articular cartilage full thickness explants were mechanically loaded, both statically and cyclically, at high frequency (2s of load with 2s intervals of no load) and low frequency (60s of load with 60s intervals of no load), at 1 MPa. Metabolic effects of the load were studied by radiolabeling and compared with non-loaded cartilage explants. High frequency load had a stimulatory effect on protein and proteoglycan synthesis while low frequency and static load showed decreased synthesis. Removing the load from the cultures restored synthesis to non-loaded control culture levels. No major differences in protein biosynthetic pattern were revealed, as determined by SDS-PAGE and fluorography, showing the generalized nature of the response.
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PMID:Effects of mechanical load on cartilage matrix biosynthesis in vitro. 178 31

Heparan sulphate proteoglycans were solubilized from whole rat livers by homogenization and dissociative extraction with 4 M-guanidinium chloride containing Triton X-100 and proteinase inhibitors. The extract was subjected to trichloroacetic acid precipitation and the proteoglycan remained soluble. This was then purified to apparent homogeneity by a combination of (a) DEAE-Sephacel chromatography, (b) digestion with chondroitinase ABC followed by f.p.l.c. Mono Q ion-exchange chromatography, and (c) density-gradient centrifugation in CsCl and 4 M-guanidinium chloride. Approx. 1.5 mg of proteoglycan was obtained from 30 livers with an estimated recovery of 25%. The purified proteoglycan was eluted from Sepharose CL6B as an apparently single polydisperse population with a Kav. of 0.19 and displayed a molecular mass of greater than or equal to 200 kDa (relative to protein standards) by SDS/PAGE. Its heparan sulphate chains were eluted with a Kav. of 0.44 and have an estimated molecular mass of 25 kDa. Digestion of the proteoglycan with a combination of heparinases yielded core proteins of 77, 49 and 44 kDa. Deglycosylation using trifluoromethanesulphonic acid, though slightly decreasing the sizes, gave an identical pattern of core proteins. Electrophoretic detergent blotting demonstrated that all of the core proteins were hydrophobic and are probably integral plasma membrane molecules. The peptide maps generated by V8 proteinase digestion of the two major core proteins (77 and 49 kDa) were very similar, suggesting that these two core proteins are structurally related.
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PMID:Purification and partial characterization of the major cell-associated heparan sulphate proteoglycan of rat liver. 184 41

A proteoglycan (PG) was purified to homogeneity from intima/media preparations of human aorta specimens by the following chromatographic steps: Sepharose Q anion exchange, Sepharose CL-4B size exclusion, hydroxyapatite, MonoQ anion exchange and TSK G 4000 SW size exclusion. The purity of the preparation was established by SDS/PAGE using direct staining by silver or Dimethylmethylene Blue, as well as by Western blots of biotin-labelled samples. The electrophoretic mobility of the native PG was less than that of a 200,000-Mr standard protein. After treatment with chondroitin sulphate lyase ABC, a core protein of Mr 15,000 was revealed. The Mr of the glycosaminoglycan (GAG) peptides was less than 24,000, by comparison with a keratan sulphate peptide. The composition of the GAG chains was determined by differential digestion of the PG by chondroitin sulphate lyases AC/ABC or chondroitin sulphate lyase AC alone followed by anion-exchange chromatography of the resulting disaccharides. The GAG chains are composed of approximately one-third of dermatan sulphate and two-thirds chondroitin sulphate disaccharide units. The sequence of the 20 N-terminal amino acids is identical with the sequence previously reported for PG I isolated from human developing bone [Fisher, Termine & Young (1989) J. Biol. Chem. 264, 4571-4576]. The assignment of glycosylation sites to the serine residues in positions 5 and 10 was confirmed. The findings indicate that the chondroitin sulphate/dermatan sulphate PG is a major PG in intima/media preparations of human aorta and represents a biglycan-type PG.
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PMID:Purification and N-terminal amino acid sequence of a chondroitin sulphate/dermatan sulphate proteoglycan isolated from intima/media preparations of human aorta. 184 58

The myeloperoxidase-derived oxidant, hypochlorite (OCl-) was shown to be able to degrade proteoglycan aggregate prepared from bovine articular cartilage. Exposure of proteoglycan aggregate to OCl- concentrations less than 10(-4) M resulted in a decrease in the size of the constituent proteoglycan monomers, which were unable to reaggregate with hyaluronate due to the loss of the hyaluronic acid binding region as indicated by immunoblotting using the monoclonal 1-C-6 antibody. Analysis of the [35S]-labeled core proteins by SDS/polyacrylamide electrophoresis and fluorography indicated a decrease in the size of the core protein. These data suggest that concentrations of OCl- below 10(-3) M results in the cleavage of the proteoglycan core protein in or near the hyaluronic acid binding region. The physiological consequences of these data are discussed. Exposure to higher concentrations (greater than 10(-3)) of OCl- caused more extensive degradation of the core protein; however, there was no evidence to suggest that OCl- cleaves glycosaminoglycan (GAG) chains.
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PMID:The oxidant hypochlorite (OCl-), a product of the myeloperoxidase system, degrades articular cartilage proteoglycan aggregate. 184 64

Gelatinase (matrix metalloproteinase 2) purified from culture medium of MDCK cells by affinity chromatography on gelatin-sepharose was tested against type XI collagen. The purified enzyme-digested native type XI collagen in solution, and as reconstituted fibers, at 30, 34, and 37 degrees C. Both substrates yielded the same digestion products, as characterized by SDS-polyacrylamide gel electrophoresis, but the soluble collagen was cleaved at a higher rate. The first major product seen was an 87-kDa peptide, which was usually associated with one or two peptides migrating between it and alpha 3(XI). With time, a second group of 3 peptides appeared at 78, 75, and 73 kDa. After continued digestion, a third group of peptides was detected with prominent 69- and 67-kDa peptides and minor peptides at 71, 65, and 62 kDa. In overnight (20 hour) digestions, the 60-kDa digestion product accumulated and most of the larger digestion products could no longer be detected. Minor products at 71, 55, and 50 kDa were also noted in these limited digestions. Under the same conditions, denatured type XI was digested to fragments smaller than 13.5 kDa. The enzyme was inhibited by 1,10-phenanthroline or EDTA. Two purified components of cartilage matrix, type II collagen and proteoglycan subunit, as well as crude cartilage homogenates, were not effective inhibitors of the purified enzyme. Similar activity was extracted from canine articular cartilage, and the activity was much stronger in cartilage from osteoarthritic joints than from control joints.
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PMID:Cleavage of type XI collagen fibers by gelatinase and by extracts of osteoarthritic canine cartilage. 185 Dec 45

Normal murine splenic T lymphocytes and T-lymphoma cells were incubated with [35S]sulphate in low-sulphate medium for 4 hr. Gel filtration and SDS-PAGE revealed that the radiolabelled macromolecules secreted by these cells were almost exclusively chondroitin sulphate and heparan sulphate proteoglycans of relatively low molecular weight (MW), 100,000-200,000. Triton X-100 extracts of the cells contained similar proteoglycans. Under the conditions employed the incorporation of radiolabel by cells grown in vivo was equally distributed between cell-retained and secreted fractions, whereas cells grown in vitro retained some 75% of incorporated label. In general heparan sulphate predominated over chondroitin sulphate in both secreted and cell-retained fractions. Cell extracts also contained a minor proportion of free glycosaminoglycan, which is almost exclusively heparan sulphate. These chains, like those incorporated into the proteoglycan, were around 12,000 MW. The T-lymphoma cells RDM-4, whether grown in vitro or in vivo, also incorporated a substantial proportion of [35S]sulphate into a single, cell-retained protein, 100,000 MW. No such radiolabelled protein was detectable in T cells.
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PMID:Murine T lymphocytes and T-lymphoma cells produce chondroitin sulphate and heparan sulphate proteoglycans and free heparan sulphate glycosaminoglycan. 190 56

The proteoglycans synthesized by an osteoblast-like cell line of rat origin (UMR 106-01) were defined after biosynthetic labelling with [35S]sulphate and [3H]glucosamine. Newly synthesized labelled proteoglycans were characterized by differential enzymic digestion in combination with analytical gel filtration and SDS/PAGE. UMR 106-01 cells were found to synthesize three major species of proteoglycan: a large chondroitin sulphate proteoglycan of Mr approximately 1 x 10(6), with a core protein of Mr approximately 350,000-400,000; a small chondroitin sulphate-containing species of Mr approximately 120,000 with a core protein of Mr 43,000; and a heparan sulphate proteoglycan of Mr approximately 150,000, with a core protein of Mr approximately 80,000. Over 70% of the newly synthesized intact proteoglycan species are associated with the cell layer of near-confluent cells; however, accessibility to trypsin digestion suggests an extracellular location. Chemical characteristics of the proteoglycans and preliminary mRNA hybridization indicate that the small chondroitin sulphate proteoglycan is probably PG II (decorin). The large chondroitin sulphate proteoglycan is most likely related to a hyaluronate-aggregating species from fibroblasts (versican), and the heparan sulphate proteoglycan bears striking similarities to cell-membrane-intercalated species described for a number of cell types.
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PMID:Proteoglycans synthesized by an osteoblast-like cell line (UMR 106-01). 190 8

The primary structure of chromogranin A indicates multiple domains which might be subject to posttranslational modification. We explored chromogranin A's proteolytic cleavage, glycosylation, and possible intermolecular disulfide links, using biochemical and cell biological approaches. Anti-chromogranin A region-specific immunoblots on chromaffin granules suggested bidirectional endoproteolytic cleavage of chromogranin A; control experiments ruled out artifactual cleavage during granule isolation or lysis. Isolation of chromogranin A-derived peptides by gel filtration chromatography or sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), followed by N-terminal amino acid sequencing, established several cleavage sites, including at least two at dibasic sites. Secretion of chromogranin A from bovine chromaffin cells did not initiate further cleavage, nor did prolonged exposure of secreted chromogranins to the secretory cells. The chromogranin A cleavage pattern was qualitatively similar in other neuroendocrine tissues, though cleavage was more complete in adrenal medullary than in anterior pituitary hormone storage vesicles, and N-terminal fragments of 45 and 55 kilodaltons were more prominent in the hypothalamus. A similar cleavage pattern was seen in human pheochromocytoma granules, as judged by chromogranin A region-specific immunoblots, fragment isolation by SDS-PAGE, and microsequencing. The presence of full-length chromogranin A as the core protein of a chromaffin granule soluble proteoglycan was suggested in bovine (but not human) chromaffin granules by glycoprotein staining, chondroitinase ABC digestion, chemical deglycosylation, and region-specific immunoblotting. Human (but not bovine) chromogranin A displayed intermolecular disulfide crosslinks on SDS-PAGE gels and immunoblotting. These results document diverse structural paths that the chromogranin A molecule may take in endocrine secretory cells after its translation.
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PMID:Chromogranin A: posttranslational modifications in secretory granules. 198 17

We have been interested in examining the putative biological role(s) of the major proteoglycan of adult skeletal muscle. The small proteoglycans of adult rabbit skeletal muscle and tendon were extracted and purified by sequential density-gradient ultracentrifugation, ion-exchange chromatography and gel filtration. They appeared to be homogeneous by the criterion of gel electrophoresis in SDS and to yield one major product, the core protein, after digestion with chondroitin ABC lyase, also observed after gel electrophoresis. Two major products were obtained when the intact proteoglycans were cleaved by CNBr, and those peptides were separated by SDS/PAGE and by ion-exchange chromatography. Sequencing of the N-terminal amino acids of either the intact proteoglycans or the CNBr-cleaved products allowed for comparison of the muscle and tendon proteoglycan with derived amino acid sequences previously reported for bovine bone proteoglycan. The bone and tendon proteoglycan sequences were remarkably similar, whereas those of the muscle proteoglycan differed from the other two molecules. The major site of glycosaminoglycan substitution was on a peptide fragment distant from the N-terminus, and a presumptive serine residue at position 4 from the N-terminus also appeared to be substituted, perhaps with a small glycosaminoglycan chain. These results provide some insight into the diversity of small proteoglycans of the PG-II class and provide a basis for exploring their mode of genetic expression.
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PMID:The major proteoglycan of adult rabbit skeletal muscle. Relationship to small proteoglycans of other tissues. 200 Dec 36

Profound changes occur in the cervix during pregnancy. In particular, the connective tissue is remodelled. To elucidate the mechanisms behind this process, the metabolism of cervical connective tissue was studied using tissue cultures. Cervical biopsies from non-pregnant and pregnant women were incubated with [35S]sulphate. The proteoglycans of the tissue specimens were purified by ion-exchange and gel chromatography and characterized by SDS/PAGE and by enzymic degradation. In the non-pregnant cervix, the incorporation of [35S]sulphate into the proteoglycans was linear for 48 h. During the first 6 h of incubation the accumulation of chiefly one small labelled proteoglycan (apparent Mr 110,000) substituted with dermatan sulphate was recorded. This is in accordance with the known proteoglycan composition of non-pregnant cervical tissue. In addition, small amounts of two larger radioactive dermatan/chondroitin sulphate proteoglycans (apparent Mr values 220,000 and greater than 500,000) were recorded. After longer periods of incubation the proportion of heparan sulphate proteoglycans increased considerably. The pregnant tissue showed a clearly different composition of labelled proteoglycans. An increased accumulation of the two larger dermatan/chondroitin sulphate proteoglycans was seen in addition to the dominant small dermatan sulphate proteoglycan of the non-pregnant cervix. The rate of accumulation of these two proteoglycans was about 3 times higher in the pregnant tissue, whereas that of the small dermatan sulphate proteoglycan was only increased 2-fold. The fact that the concentration of proteoglycans in the pregnant cervix is approximately one-half of that in the non-pregnant cervix indicates that the turnover of proteoglycans in pregnant cervical tissue is significantly increased. The major effect of this profound change of metabolism was a 50% decrease in proteoglycan content and a 2-fold increased proportion of a dermatan sulphate proteoglycan with an apparent Mr of 220,000.
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PMID:Proteoglycan metabolism in the connective tissue of pregnant and non-pregnant human cervix. An in vitro study. 202 30


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