Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “collagen”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1977

Procollagen and collagen produced by a teratocarcinoma-derived cell line, TSD4: evidence for a new molecular form of collagen.

Procollagen and collagen were isolated from the culture medium and cell layer of line TSD4 (obtained from mouse teratocarcinoma OTT6050). SDS-polyacrylamide gel electrophoresis of the highly purified procollagen fraction demonstrated that the fraction is composed of theta chains (150,000 daltons), pro alpha chains (130,000 daltons), and alpha chains (100,000 daltons). Limited pepsin digestion of this fraction yielded a single species of collagen molecules having a chain composition (alpha1)3, as did collagen isolated from the cell layer. Each alpha1 chain appears to be slightly larger than alpha1 chains from calf or human type I and type III collagen. Amino acid analysis and cyanogen bromide peptide profiles of pepsin-treated TSD4 collagen demonstrated significant differences from those of other collagens (II, III, IV) of the type alpha1(X)3, although similar to that of the alpha1 chain of type I collagen, [alpha1(1)]2alpha2. Taken together, acrylamide gel electrophoresis, amino acid composition, electron microscopy, and cyanogen bromide peptide analysis indicate that this material represents a new molecular species of collagen not previously characterized, probably related to [alpha1(I)]3.

Amino Acids↗
PubMed1976

On the role of the collagen carbohydrate residues in the platelet. Collagen interaction.

It has been proposed that the platelet : collagen interaction is mediated in part by the collagen carbohydrate residues. To test this hypothesis we have oxidized monomeric and polymeric collagen with sodium periodate under conditions specifically designed to minimize destruction of periodate-susceptible bonds other than in the carbohydrate residues. Oxidation of the collagen significantly reduced its ability to interact with platelets. The extent of inhibition paralleled the extent of carbohydrate destruction. Oxidation with periodate also delayed the polymerization of the monomeric collagen, but even after polymerization the oxidized collagen failed to initiate the release reaction. These observations suggest that the collagen carbohydrate residues may be either near to or part of the site(s) on the collagen molecule required for platelet adhesion.

Binding Sites↗
PubMedDate not supplied

[Biosynthesis of collagen and non-collagen proteins on free and bound polysomes from chick embryo].

Synthesys of collagen and non-collagen proteins was investigated in a cell-free system in the presence of free and bound polysomes isolated from chick embryos. Of total radioactive proteins synthesized on bound and free polysomes the amount of peptides digested by bacterial collagenase comprised 25-40% and 5-7% respectively. These data showed that collagen was predominantly synthesized by bound polysomes. Free polysomes were found to be much more active than bound ones in non-collagen protein synthesis. When bound polysomes detached from membranes by detergent treatment were incubated in a cell-free system, a release of non-collagen proteins into the incubation medium increased sharply, but the release of collagen peptides was as negligible as in the case of untreated polysomes. Kinetic studies of collagen synthetizing activity of polysomes bound to or detached from membranes suggested the role of endoplasmic membranes in stabilizing collagenous polysomes.

Animals↗
PubMedDate not supplied

Leucocyte migration inhibition with collagen type I and collagen type III in rheumatoid arthritis and degenerative joint diseases.

The leucocytes of 22 patients with classic rheumatoid arthritis were investigated with the direct leucocyte migration inhibition technique in agarose as described by Clausen. The leucocytes of 9 patients with degenerative joint diseases and of 9 healthy persons served as controls. Collagen type I and collagen type III were used as antigens. The leucocytes of 22 patients with rheumatoid arthritis showed in 15 cases a migration inhibition with collagen type III and in 10 cases with collagen type I. The inhibition with collagen type III was stronger and more frequent than with collagen type I. The frequent leucocyte migration inhibition with collagen type III in classic rheumatoid arthritis seems to be an expression of possible cell mediated reactivity against that type of collagen which appears especially in rheumatoid synovial tissue.

Adult↗
PubMed1976

Light microscopic distinction between elastin, pseudo-elastica (type III collagen?) AND INTERSTITIAL COLLAGEN.

Distinction between elastin and collagen in arteriosclerotic lesions is difficult because the so-called elastica stains are bound also by collagen fibers which resemble collagen of premature infants. Investigations of effects of organic solvents on dye binding led to the development of methods for selective demonstration of pseudo-elastica, and for simultaneous visualization of elastin and pseudo-elastica in contrasting colors. Paraffin sections of human autopsy material were stained with solutions of resorcin-fuchsin, orcein or aldehyde fuchsin in absolute ethanol. In other series, sections pretreated with this resorcin-fuchsin solution were counter-stained with tannic acid-phosphomolybdic acid (TP)-dye technics. Solutions of these "elastica stains" in absolute ethanol colored only pseudo-elastica; elastin, e.g. elastic membranes of aorta, remained unstained. In sections counterstained with TP-dye technics elastin was colored red; pseudo-elastica retained the purplish blue coloration imparted by resorcin-fuchsin. Other collagens were stained yellow. A review of the literature showed that until the 1920's elastin was classified as a gelatinoid of the collagen group. Elastic fibers were identified by mechanical properties, not a particular chemical composition. Hence, the elastic fibers of classical histology cannot be equated with the elastin of modern chemistry. Correlation of histochemical observations with chemical data indicates that the collagenous pseudo-elastica corresponds to [alpha1(III)]3 collagen.

Adult↗
PubMed1977

The solubilization of bone and dentin collagens by pepsin. Effect of cross-linkages and non-collagen components.

Bone and dentin collagen are less susceptible to solubilization by pepsin digestion then is skin collagen. Digestion at 4 degrees C for 72 h solubilized only 35.3% of bovine cortical bone and 5.6% of bovine dentin compared with nearly 100% dissolution of bovine skin. Sodium dodecyl sulfate-acrylamide gel electrophoresis and molecular sieve chromatography showed that, for bone and dentin, intact alpha chains and cross-linked aggregates of beta, gamma and higher weight remained intact after pepsin solubilization but lower molecular weight fragments also were prevalent indicating chain scission in helical regions. Electron microscopic examination of segment long spacing precipitates of the soluble collagens confirmed the presence of solubilized polymerized collagen. The principal reducible cross-link in both bone and dentin was the precursor of dihydroxylsinonorleucine and this cross-link was also present in the solubilized collagens. Small amounts of non-collagenous proteins and glycosaminoglycans of different compositions in dentin and bone resisted extraction before pepsin digestion. However, the differences in solubilization of the collagens have been related to differences in cross-linkage placement.

Amino Acids↗
PubMed1979

Collagen synthesis by cultured skin fibroblasts from siblings with hydroxylysine-deficient collagen.

It has been previously shown that dermis from subjects with hydroxylysine-deficient collagen contains approximately 5% of normal levels of hydroxylysine and sonicates of skin fibroblasts contain less than 15% of normal levels of collagen lysyl hydroxylase activity. However, cultures of dermal fibroblasts from two siblings with hydroxylysine-deficient collagen (Ehlers-Danlos Syndrome Type VI) compared to fibroblasts from normal subjects synthesize collagen containing approximately 50% of normal amounts of hydroxylysine. The lysyl hydroxylase deficient cultures synthesize both Type I and Type III collagen in the same proportion as control cultures. Both alpha 1(I) and alpha 2 chains are similarly reduced in hydroxylysine content. Collagen prolyl hydroxylation by normal collagen lysyl hydroxylation is the same with or without ascorbate supplementation. In mutant cells the rate of prolyl hydroxylation measured after release of inhibition by alpha, alpha'-dipyridyl is the same as in control cells. The rate of lysyl hydroxylation is reduced in mutant cells but only to approximately 50% of normal.

Ascorbic Acid↗
PubMed1979

Characterization of a novel collagen chain in human placenta and its relation to AB collagen.

A novel collagen chain, termed alpha C, has been isolated from human placenta by limited pepsin digestion. The collagen containing the alpha C chain copurifies with placental AB collagen during selective salt precipitation but is virtually absent from fetal birth membranes, which contain relatively larger amounts of AB. Both native AB and alpha C-containing collagens are resistant to human skin collagenase under conditions that support cleavage of type I by greater than 90%. The alpha C chain was separated from alpha B by phosphocellulose chromatography and subsequently from alpha P by chromatography on CM-cellulose. Its amino acid composition is distinct from alpha A and alha B although all three chains posses compositional features in common; the carbohydrate content of the alpha C chain was intermediate between those of alpha A and alpha B. Analysis by NaDodSO4-polyacrylamide gel electrophoresis of peptides produced by CNBr cleavage and by limited digestion with the enzyme mast cell protease indicated different and unique products for the alpha A, alpha B, and alpha C chains. The data support the existence of another collagen chain which is related to the alpha A and alpha B chains but which is structurally unique. The proteins containing these chains may in turn comprise a subfamily of collagen isotypes which represents a divergence from and/or specialization of the type IV basement membrane collagens.

Amnion↗
PubMed1979

Inhibition of collagen-induced platelet aggregation by antibodies to distinct types of collagens.

Aggregation of platelets by fibrils formed from collagens type I, II and III could be inhibited by coating the fibrils with anti-collagen antibodies or Fab fragments. Similar results were obtained in a clot-retraction assay. Inhibition was achieved with stoichiometric amounts of antibodies and was specific for each type of collagen. Aggregation caused by a mixture of type-I and -III collagens could only be inhibited by a mixture of antibodies against both collagens. The data show that each interstitial collagen is capable of interacting with platelets and do not support the concept of an outstanding activity of type-III collagen.

Antibodies↗
PubMed1978

Chemotactic attraction of human fibroblasts to type I, II, and III collagens and collagen-derived peptides.

The chemotactice response of human dermal fibroblasts of type I, II, and III human collagens and collagen-derived peptides was quantitated by an in vitro assay. All three native human collagens and constituent alpha chains can serve as chemoattractants for fibroblasts in vitro. When type I, II, and III collagens were digested by bacterial collagenase, the resulting peptides were also chemotactic. In addition, synthetic di- and tripeptides containing hydroxyproline were also chemotactic for fibroblasts. Since collagen is degraded and remodeled at sites of tissue injury and inflammation, these findings suggest that collagen and collagen-degradation peptides might function as chemotactic stimuli for fibroblasts in vivo and attract these cells to effect repair of damaged tissue.

Cell Line↗
PubMed1976

Abnormal properties of collagen lysyl hydroxylase from skin fibroblasts of siblings with hydroxylysine-deficient collagen.

Skin fibroblasts from two siblings with hydroxylysine-deficient collagen collagen (Ehlers-Danlos syndrome, type VI) contained normal levels of collagen prolyl hydroxylase activity but were markedly deficient in collagen lysyl hydroxylase activity. The deficiency was evident in all fractions of cell lysates, in low and high ionic strength buffers, and in detergent. Assays of mixtures of wild-type and mutant cell lysates indicated no activation of mutant enzyme by factors in wild-type cells or inhibition of normal enzyme by material in mutant cells. Wild type or mutant cells cultured with ascorbic acid (50 mug/ml of culture medium, added daily) contained approximately the same level of lysyl hydroxylase activity as cells cultured without ascorbate, but prolyl hydroxylase activity without ascorbate was depressed in both an average of 41%. The mutant lysyl hydroxylase was less stable at 37 degrees C than the wild type and did not form high molecular weight aggregates in low ionic strength buffers, as did the control enzyme. The activity of the mutant enzyme was maximally stimulated after dialysis against buffer solutions containing 10 mM dithiothreitol. When assayed in 100 muM dithiothreitol, the mutant enzyme exhibited a higher apparent Km for ascorbate (20 muM) than the wild type (4 muM). In 1.0 mM dithiothreitol the mutant enzyme's apparent Km for ascorbate was reduced to 5 muM. Wild type and mutant enzymes had the same apparent Km for alpha-keto-glutarate (20 muM). The properties of prolyl hydroxylase in wild type and mutant cells were identical: apparent Km's for ascorbate and alpha-ketoglutarate were 100 muM and 20 muM, respectively. If mutant enzyme protein with altered kinetic properties is the only enzyme functioning to hydroxylate lysyl residues in collagen, the variations in hydroxylysine content observed in collagen from different tissues in the subjects reported here could be in part due to differences in cofactor concentrations and in rate and sequence of events in collagen synthesis in different tissues.

Ascorbic Acid↗
PubMed1976

The cyanogen bromide peptides of bovine soluble and insoluble collagens. II. Tissue specific cross-linked peptides of insoluble skin and dentin collagen.

Cyanogen bromide peptides were prepared from insoluble bovine skin and dentin collagens and compared by electrophoresis in polyacrylamide gels containing sodium dodecylsulphate, with those of the alpha1 and alpha2 chains of soluble type I and type III collagen. Both insoluble collagens yielded predominantly the peptides of type I collagen. Insoluble skin collagen was approximately 13% type III. Type III collagen if present in dentin, is present in smaller quanitity not detected by the technique used here. Several new fragments, different in each tissue, were obtained which could not be accounted for as uncleaved peptides. Three of those from dentin were isolated by gel chromatography and characterized by amino acid analysis. Two were found to contain 3-hydroxyproline, suggesting the presence of alpha1CB6. The recovery of only 25-30% of alpha1CB6 in the expected position on SDS gel electrophoresis indicated that it was involved in interactions with other peptides in these two tissues to the extent of one and a half cross-links per tropocollagen molecule. The nature and distributin of cross-link peptides of bovine skin and dentin collagens was distinctly different.

Amino Acids↗
PubMed1976

Collagen cross-linking. Synthesis of collagen cross-links in vitro with highly purified lysyl oxidase.

In this paper, the synthesis of collagen cross-links in vitro was investigated in a defined system consisting of highly purified chick cartilage lysyl oxidase and chick bone collagen fibrils. Cross-link synthesis in vitro was quite similar to the biosynthesis of collagen cross-links in vivo. Enzyme-dependent synthesis of cross-link intermediates and cross-linked collagen derived from lathyritic collagen occurred. The concentration of the two principal reducible cross-links, N6:6'-dehydro-5,5'-dihydroxylysinonorleucine and N6:6'-dehydro-5-hydroxylysinonorleucine, increased to a peak value of approximately two cross-links per molecule and then decreased. Synthesis of histidinohydroxymerodesmosine and a second polyfunctional cross-link of unknown structure began after synthesis of bifunctional cross-links was largely completed and proceeded linearly afterwards. Inhibition of lysyl oxidase after the bulk of bifunctional cross-link synthesis had occurred did not alter the rate of decrease in reducible cross-link concentration but did inhibit further histidinohydroxymerodesmosine synthesis. These results indicate that lysyl oxidase and collagen fibrils are the only macromolecules required for cross-link biosynthesis in vivo. It is likely that the decrease in reducible cross-links observed during fibril maturation results from spontaneous reactions within the collagen fibril rather than additional enzymatic reactions.

Amino Acid Oxidoreductases↗
PubMed1979

Collagen-induced arthritis in rats. Comparison of vitreous and cartilage-derived collagens.

An oil emulsion of purified type II collagen from bovine articular cartilage when injected intradermally into rats induced an inflammatory polyarthritis in 4 of 12 animals. When similarly injected, collagen purified from bonve vitreous induced arthritis in 6 of 12 animals. Studies of humoral and cell-mediated immunity to both collagen preparations demonstrated complete cross-reactivity. It is concluded that vitreous collagen shares the arthritogenic property of cartilage-derived type II collagen and that collagen from the two sources is indistinguishable in arthritogenic and immunologic properties.

Animals↗
PubMed1977

Age-related changes in human skin collagen galactosyltransferase and collagen glucosyltransferase activities.

Collagen galactosyltransferase and collagen glucosyltransferase activities were assayed in human skin specimens of about 100 mg wet weight. The assay of the glucosyltransferase activity was found to be highly specific. The assay of the galactosyltransferase activity was somewhat less specific, but there was no difference in specificity between the foetal and adult human skin samples. The activities of the two collagen glycosyltransferases in human skin extract were found to vary with age, being highest in foetal skin, and higher in the skin of young children that in that of adults. The galactosyltransferase and glucosyltransferase activities in foetal skin were respectively about 4 times and 6 times those in adult skin. The magnitudes of the changes with age in the two collagen glycosyltransferase activities were smaller than those occurring in the activities of the two other intracellular enzymes of collagen biosynthesis namely prolyl and lysyl hydroxylase. This difference suggests that the four intracellular enzyme activities of collagen biosynthesis are not regulated in an identical manner.

Adolescent↗
PubMed1976

Cleavage of Type II and III collagens with mammalian collagenase: site of cleavage and primary structure at the NH2-terminal portion of the smaller fragment released from both collagens.

Collagenase cleavage of human Type II and III collagens has been studied using a highly purified preparation of rabbit tumor collagenase. Progress of the reactions in solution was followed by viscometry and the results indicated that under the conditions employed Type III collagen molecules were cleaved at approximately five times the rate of Type II molecules. Cleavage products of the reactions were isolated in denatured form by agarose molecular sieve chromatography. The molecular weights and amino acid compositions of the products demonstrated that Type II and III molecules had been cleaved at the characteristic three-quarter, one-quarter locus, giving rise to a large fragment derived from the NH2-terminal portion of the molecule and a smaller fragment representing the COOH-terminal region. The amino acid sequence at the NH2-terminal portion of the smaller fragment derived from Type II collagen was determined to be Ile-Ala-Gly-Gln-Arg, and the corresponding region from Type III collagen was found to have the sequence Leu-Ala Gly-Leu-Arg. These sequences for alpha1(II) and alpha1(III) chains adjacent to the site of collagenase cleavage along with previous data for alpha1(I) and alpha2 chains indicate that the minimum specific sequence required for collagenase cleavage is Gly-Ile-Ala or Gly-Leu-Ala. Inspection of the available sequence data for collagen alpha chains indicates that the latter sequences are found in at least three additional locations at which collagenase cleavage does not occur. Each of the sequences which are apparently not substrates for collagenase, however, are followed by a Gly-X-Hyp sequence. We suggest, then, that a minimum of five residues in collagen alpha chains COOH-terminal to the cleavage site comprise the substrate recognition site.

Amino Acid Sequence↗
PubMed1979

Metabolism of rabbit skin collagen. Differences in the apparent turnover rates of type-I- and type-III-collagen precursors determined by constant intravenous infusion of labelled amino acids.

Growing rabbits were infused for up to 10 h with labelled proline, tyrosine and leucine to achieve plateau conditions within body free pools, for [3H]proline infusion, blood free-proline specific radioactivity remained constant after about 1 h. For individual animals, type-I- and type-III-collagen precursors were isolated by precipitation with (NH4)2SO4 and DEAE-cellulose chromatography. Experiments where 3H- and 14C-labelled proline and tyrosine were infused concurrently for different periods of time showed that type I procollagen reached plateau specific radioactivity within 3 h and 90% of the plateau value after 2 h infusion, corresponding to a calculated apparent t 1/2 of less than 26 min. Plateau values for type I procollagen were taken as precursor amino acid pool specific radioactivities. The type-III-collagen-precursor fractions consistently showed lower rates of label incorporation and, by assuming that both type I and type III collagens are synthesized from the same amino acid pools, kinetic analysis revealed an apparent t 1/2 for the isolated type-III-collagen precursors of 3.9 h. For proline, there were large variations between animals in the ratio between the precursor pool for collagen synthesis and the skin homogenate free pool (0.31 +/- 0.13, mean +/- S.D.), so that collagen-synthesis rates based solely on total tissue free-pool values for proline are subject to large and inconsistent errors.

Amino Acids↗
PubMed1978

Increased solubility of collagen. A biochemical defect in the experimental hydralizine-induced collagen disease-like syndrome.

An increase of soluble fractions of collagen and a decrease of insoluble ones was found in the skin of guinea pigs with collagen disease-like syndrome, produced by prolonged treatment with hydralazine. Chromatography studies showed that the collagen alpha chains content in the skin increased and beta-chains decreased under conditions of the development of lupus-like syndrome. The obtained results suggested the inhibition of collagen maturation as one of biochemical defects of connective tissue in drug-induced collagen disease-like syndrome.

Animals↗