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Query: UNIPROT:P00790 (PGA)
 2,475 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mouse antibodies to soluble bovine skin (type I) collagen react with determinants which are located in the rigid triple-helical portion of the antigen and become destroyed upon unfolding the molecule. Helical antigenic determinants are dependent on the genuine chain assembly, e.g. alpha[1(I)]2alpha2. Artefactual triplehelical structures of the composition [alpha1(I)]3 or [alpha2]3 or a genetically distinct type II collagen from cartilage showed no or only weak cross-reactivity. Pepsin treatment of type I collagen known to remove short, non-helical sequences at both ends of the molecule had virtually no effect on antigenicity and immunogenic activity. A radioimmunoassay failed to detect antibodies in three congenic resistant mouse strains immunized with denatured type I collagen. These strains had been previously classified as high or low responders to native type I collagen. Agglutination titres vs denatured collagen culd already be demonstrated in nonimmune sera. The agglutinating activity was labile against heating at 56 degrees and could not be increased by immunization. Two out of five inbred strains showed a high response against pepsin-dissolved bovine type II collagen with the chain composition [alpha1(II)]3. Lack of correlation in the responder state to both collagen types indicated control by different immune response genes. Antibodies to type II collagen also reacted against triple-helical antigenic determinants and showed neglible cross-reaction with type I collagen.
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PMID:Specificity of the antibody response in inbred mice to bovine type I and type II collagen. 5 15

Isolated human glomeruli were digested with purified bacterial collagenase yielding epithelial cells. These cells grew to saturation density and did not become multi-layered. They were identified as visceral glomerular epithelial cells by their morphologic appearance by phase and electron microscopy and by the presence of surface receptors for C3b. Neither Factor VIII antigen nor Fc receptors were observed. The glomerular epithelial cells synthesized a collagenous protein that was antigenically similar to human glomerular basal lamina. Proteins precipitated from visceral epithelial cell medium with affinity purified antibody against noncollagenous glomerular basal lamina antigens yielded a single collagenase labile protein that by sodium dodecyl sulfate/polyacrylamide gel electrophoresis migrated with an apparent Mr of 168,000 in the presence of reducing agents. Analysis of hydroxyproline isomers yielded a ratio of 3-hydroxyproline to total hydroxyproline of 0.17. Pepsin digestion yielded a disulfide-bonded multimer which, with reduction, migrated with an apparent Mr of 148,000. These data demonstrate that human glomerular visceral epithelial cells can be isolated and propagated in vitro and that they synthesize a collagen similar to that found in vivo.
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PMID:Human glomerular visceral epithelial cells synthesize a basal lamina collagen in vitro. 9 Nov 67

We have isolated a large noncollagenous glycoprotein, laminin, from a mouse tumor that produces basement membrane. The protein consists of at least two polypeptide chains (Mr = 220,000 and Mr = 440,000) joined to each other by disulfide bonds. Laminin and type IV collagen are major constituents of the tumor. Laminin is distinctly different from fibronectin, another component of basement membranes, in amino acid composition and immunological reactivity. Pepsin digestion of laminin releases a large, cystine-rich fragment which retains most of the antigenicity of the original protein. Immunological studies using purified antibody against laminin show that it is produced by a variety of cultured cells. In addition, these antibodies react with the basement membranes of normal tissues, suggesting that this protein or an immunologically related protein is a constituent of the basement membranes of these tissues.
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PMID:Laminin--a glycoprotein from basement membranes. 11 18

Porcine aortae were digested with pepsin and the solubilised collagen molecules separated by differential salt precipitation at pH7.5. The fraction precipitated at 1.71 M NaCl was shown to comprise collagen type III as judged by its elution characteristics from CM-cellulose, its alpha-chain composition on sodium dodeclysulphate polyacrylamide gel electrophoresis, and amino acid analyses. Pepsin-derived type I collagen was recovered by precipitation at 2.56 M NaCl and similarly characterised. cultures of porcine arterial smooth muscle cells have been established and radiolabelling studies with [14Clproline have demonstrated that these cells synthesis and secrete the precursors of collagen types I and III into the culture medium. Ion-exchange chromatography of these secreted collagen molecules and gel filtration of their pepsin-derived alpha-chains have demonstrated that type III is the major collagen species present in the medium.
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PMID:Characterisation of the major collagen species present in porcine aortae and the synthesis of their precursors by smooth muscle cells in culture. 14 63

Metabolic degradation of prelabeled collagen in whole body skin and whole intestine was compared to that of types I and III collagens from skin in young, rapidly growing rats. Pregnant rats were given [3H]proline during the last week of gestation; and after birth, littermates were compared. Between the second and sixth weeks of age, there was a 43% loss of radioactivity from dermal collagen but no significant loss of radioactivity from intestinal collagen. Pepsin treatment solubilized 90% of the dermal collagen but only 12% of intestinal collagen. Skin from 2- and 6-week-old rats yielded the same proportions of type I and type III collagens (type I, 82%; type III, 18%). The relative losses of total radioactivity from types I and III were similar to each other (50 and 44%, respectively) and to the loss from whole skin. Because types I and III collagens are known to be present in both skin and intestine, the marked degradation of both collagen types in skin but not in the intestine may be related to the amount and kind of intermolecular crosslinks present.
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PMID:Collagen degradation in rat skin but not in intestine during rapid growth: effect on collagen types I and III from skin. 26 84

Pepsin-soluble collagen was isolated from bovine vitreous humor. This collagen showed only one alpha-chain in disc electrophoresis, migrating in the alpha1-chain position and between the alpha- and beta-components some colored bands were visible. The disc electrophoretic patterns of the cyanogen bromide peptides of pepsin-soluble vitreous body collagen and pepsin-soluble type II collagen revealed no identity.
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PMID:[Comparison of the cyanogen bromide peptides of vitreous body collagen and type II collagen (author's transl)]. 34 37

Sequential extraction of mature rabbit corneal stroma with NaCl-Tris buffer and acetic acid solubilized only 12% of the total corneal collagen. Pepsin (E:S 1:10,4 degrees C, 48 hr) in 0.4 M acetic acid solubilized 91% to 95% of the total collagen in the residue. Approximately 68% of the solubilized material could be precipitated at 2.5M NaCl and a further 3% to 9% at 3.5M NaCl. The collagenous material precipitating at 2.5M NaCl contained alpha, beta, gamma, and some higher molecular weight components and had a CNBr profile similar to bovine type I skin collagen. It had an hydroxylysine/lysine (OHLys/Lys) ratio of 0.43, similar to that of skin collagen, but unlike skin collagen was 52% glycosyled. Although the 3.5M NaCl precipitate had a CNBr peptide profile similar to that of type I collagen, it contained two additional collagen chains of molecular weight approximately 140,000 and 100,000 daltons, had an OHLys/Lys ratio of 0.62, and was 66% glycosylated. Individual chains were separated from the collagen precipitates by gel electrophoresis,and the additional collagen chains were shown to be carbohydrate rich. These additional collagen chains may be derived from one or more molecular species which are physiologically important in the maintenance of the unique organization of corneal collagen.
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PMID:Collagen polymorphism in mature rabbit cornea. 34 41

Endothelial cells isolated from bovine aorta synthesize and secrete type III procollagen in culture. The procollagen, which represents the major collagenous protein in culture medium, was specifically precipitated by antibodies to bovine type III procollagen and was purified by diethyl-aminoethylcellulose chromatography. Unequivocal identification of the pepsin-treated collagen was made by direct comparison with type III collagen isolated by pepsin digestion of bovine skin, utilizing peptide cleavage patterns generated by vertebrate collagenase, CNBr, and mast cell protease. The type III collagen was hydroxylated to a high degree, having a hydroxyproline/proline ratio of 1.5:1.0. Pulse-chase studies indicated that the procollagen was not processed to procollagen intermediates or to collagen. Pepsin treatment of cell layers, followed by salt fractionation at acidic and neutral pH, produced several components which were sensitive to bacterial collagenase and which comigrated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with alpha A, alpha B, and type IV collagen chains purified from human placenta by similar techniques. Bovine aortic endothelial cells also secreted fibronectin and a bacterial collagenase-insensitive glycoprotein which, after reduction, had a molecular weight of 135,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (using procollagen molecular weight standards) and which was not precipitable by antibodies to cold-insoluble globulin or to alpha 2-macroglobulin. Collagen biosynthesis by these cells provides an interesting model system for studying the polarity of protein secretion and the attachment of cells to an extracellular matrix. The presence of type III collagen in the subendothelium and the specific interaction of this protein with fibronectin and platelets suggest the involvement of this collagen in thrombus formation following endothelial cell injury.
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PMID:Collagen synthesis by bovine aortic endothelial cells in culture. 39 Dec 67

Collagen synthesis was studied in monolayer cultures of rabbit corneal endothelial cells by following [14C]proline and [3H]glucosamine or [3H]fucose incorporation into a fraction enriched for collagen and its precursor molecules. Sodium dodecyl sulfate gel electrophoresis of this fraction showed that it consisted of a high-molecular-weight (greater than 300,000 daltons) polypeptide. This component was collagenase sensitive and, in the presence of dithiothreitol, gave rise to two polypeptides of the apparent molecular weights of 200,000 and 160,000 daltons. Pepsin digestion of this material destroyed all the high-molecular-weight material and gave rise to a single collagenase-sensitive component of an apparent molecular weight of 115,000 daltons. This 115,000 dalton material is similar to previously observed basement membrane collagens, and the 160,000 and 200,000 dalton components are probably precursor chains of basement membrane collagen. The very-high-molecular-weight material (greater than 300,000 daltons) may represent a disulfide-linked complex of these precursor chains. DEAE-cellulose column chromatography confirmed the presence of a single procollagen species distinct from the collagen fraction. Amino acid analysis of collagen and procollagen fractions showed a decreased hydroxyproline value as compared with previously reported basement membrane collagens or collagen precursors.
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PMID:Biochemical characterization of procollagen-collagen synthesized by rabbit corneal endothelial cells in culture. 75 87

Human nucleus pulposus and annulus fibrosus, obtained at autopsy from patients 7-30 years of age, were extracted with 2 M guanidine-HCl (pH 5.82) to remove proteoglycans, then stirred with pepsin in 0.5 M acetic acid, followed by three 24-h extractions with 1 M NaCl (pH 7.5) and one 24-h extraction with 2 M KSCN (potassium thiocyanate) (pH 7.2). Pepsin and NaCl solubilized an average of about 30% of nucleus pulposus collagen and 18% of annulus fibrosus collagen. KSCN extracted a further 34% of nucleus pulposus collagen and only 4% of annulus fibrosus collagen. CM-cellulose chromatography of nucleus and annulus collagen purified from the pepsin, NaCl and KSCN supernatants consistently revealed only one peak, always appearing slightly ahead of the alpha1 position for rat tail tendon type I collagen. Polyacrylamide and SDS-gel electrophoresis consistently revealed only one band with the mobility of alpha1 chains. Amino acid composition of collagen from nucleus and annulus is comparable to those of mammalian and avian cartilage type II collagen, and distinctly different from those of rat tail tendonand guinea pig skin type I collagens. Periodate oxidation of nucleus and annulus collagens showed that 81% and 67%, respectively, of the hydroxylysine residues survive treatment, compared to 71% for bovine articular cartilage collagen and 17% for guinea pig skin collagen. Total hexose analysis revealed 1.8 muM and 2.0 muM hexose per muM periodate-stable hydroxylysine in nucleus and annulus collagens, respectively. Ion exchange chromatography showed the presence of glucose and galactose in a ratio of 0.92:1 in nucleas collagen and 1.07:1 in annulus collagen. Pepsin-solubilized, NaCl-extracted collagen from nucleus and annulus formed native-type fibrils in vitro. The banding patterns of ATP-induced segment-long-spacing precipitates of nucleus and annulus collagens were identical to each other and indistinguishable from those of cartilage (type II) collagen, but distinctly different from those of rat tail tendon (type I) collagen. These data suggest that the collagen which can be extracted after limited pepsin attack of human nucleus and annulus is of the form [alpha1 (II)]3.
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PMID:Pepsin-solubilized collagen of human nucleus pulposus and annulus fibrosus. 78 25


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