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:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ends of ruptured human tendons have been examined by scanning electron microscopy. The collagen fibres taper markedly, often leading up to a coiled segment or a knot of collagen at the point of rupture. This tapering of the collagen fibres was shown to be typical of denatured collagen by its selective removal by trypsin digestion. This denaturation caused by mechanical rupture was shown to be localized at the point of rupture, the rest of the collagen fibre remaining in the native state. The possible significance of these observations to the healing of ruptured tendons is discussed.
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PMID:Evidence for the local denaturation of collagen fibrils during the mechanical rupture of human tendons. 114 Aug 33

1. Radioactivity from [3H]glucosamine is rapidly incorporated into cellular fractions of lens epithelial cells cultured in vitro. The incorporated isotope appears largely in glycoproteins of the cell surface that are exposed to trypsin and are released into a soluble form by proteolysis of intact cells. Glycoproteins are also secreted by cultured cells and can be recovered in the culture fluids. Sodium dodecysulphate-polyacrylamide gell electrophoresis shows that a range of glycoproteins with apparent molecular weights from approximately 14000 to 120000 are present. The relationships of these glycoproteins to collagen and the non-collagenous glycoproteins of lens basement membranes are discussed. 2. A plasma membrane fraction obtained from non-trypsinised lens epithelial cells contains one major glycoprotein of apparent molecular weight 120000. A major non-glycosylated polypeptide of molecular weight about 38000 detectable by Bloemendal et al. (1972) in plasma membranes of differentiated lens fibre cells was not prominent in lens epithelial cell membranes. 3. Examination of lens basement membranes extracted in various ways failed to reveal major glycoproteins of low molecular weight. Higher molecular weight glycoproteins, some of them related to collagen, were present.
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PMID:Lens glycoproteins: biosynthesis in cultured epithelial cells of bovine lens. 116 11

1. The insoluble collagen from Guerin epithelioma was isolated and its chemical composition was determined. The unusually high histidine content is accompanied in tumour collagen by a relatively small amount of lysine and arginine. 2. The isolated protein was strongly bound to glycoprotein, which could not be removed by EDTA treatment unless this procedure was preceded by digestion of the complex with trypsin.
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PMID:Isolation, purification and chemical composition of insoluble collagen from Guerin epithelioma. 117 10

Collagen fibres from rat tail tendon suspended in small pieces in a solution (pH 7.8) containing 0.5 M CaCl2 were treated with purified bovine trypsin at 20 degrees C for 20 h. After the enzyme treatment collagen from this solution was precipitated out and reconstituted in vitro into native-type fibrils. The banding pattern in these reconstituted fibrils was found to be oblique. This is comparable to that observed recently in fibrils reconstituted from cartilage collagen. On the other hand, normal transverse banding pattern was observed in the fibrils reconstituted in vitro from collagen solution of rat tail tendon which was not pre-treated with trypsin. No significant change was, however, observed in the segment long spacing fibrils precipitated from the enzyme-treated collagen solution. It is possible that the enzyme might affect the mode of organization of tropocollagen molecules during in vitro fibrillogenesis into native-type fibrils either by interacting with the "telopeptide" regions or with the non-collagenous components associated with the native protein and this could probably result into the formation of fibrils with oblique banding pattern.
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PMID:Oblique banding pattern in collagen fibrils reconstituted in vitro after trypsin treatment. 118 Sep 59

The cyanogen-bromide-derived peptide alpha2-CB4 from calf skin collagen, consisting of 321 amino acid residues, has been fragmented in order to obtain peptides suitable for automated sequential analysis. Digestion with chymotrypsin liberated six unique peptides consisting of 12, 17, 19, 54, 63 and 156 amino acid residues. Treatment of alpha2-CB4 with hydroxylamine yielded four peptides with 24, 87, 96 and 114 residues. No unspecific cleavage by hydroxylamine was encountered. All of the trypsin-derived peptides of alpha2-CB4 were isolated and characterized by their amino acid compositions. Most of the peptides isolated were ordered along the peptide chain of alpha2-CB4. Ordering of the peptides was greatly assisted by the isolation of double peptides from the chymotrypsin, trypsin and hydroxylamine-derived peptide mixtures.
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PMID:The covalent structure of collagen. The chymotrypsin, trypsin and hydroxylamine peptides derived from alpha2-CB4 of calf-skin collagen. 120 2

Fluorescent-labelled polymeric collagen fibrils have been prepared which contain three fluoresein residues in the telopeptide regions and four fluorescein residues in the helical region of each tropocollagen unit within the polymer. This material has been used as a substrate for the study of enzymes present in the synovial fluid of inflamed rheumatoid joints which are capable of degrading polymeric collagen fibrils. Two enzyme systems were observed, one inhibited by EDTA and having the properties of the known synovial collagenase, the other having the properties of a neutral protease. The neutral protease was found to be present in sonicates of the polymorphonuclear leucocytes in the synovial fluids of inflamed joints. This enzyme attacked the telopeptides of fluorescein-labelled polymeric collagen fibrils and was similar to trypsin in removing two residues of fluorescein-labelled peptides per tropocollagen molecule within the polymeric collagen fibrils but did not depolymerise the polymeric collagen fibrils.
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PMID:A neutral protease in rheumatoid synovial fluid capable of attacking the telopeptide regions of polymeric collagen fibrils. 123 47

Guinea-pig peritoneal exudate cells were tested in vitro in the presence or absence of specific antiserum to native collagen for their capacity to discriminate between native and denatured collagens of various species. Adherent exudate cells bound denatured collagens, regardless of the origin of the collagen or the presence of serum. The binding was reduced if the cells were pretreated with trypsin. Recovery of binding was mediated by a normal serum component resembling an IgM antibody to denatured collagen. In the presence of normal serum, native collagen was only marginally bound, apparently in a non-specific manner. Uptake of native heterologous collagens was greatly increased in the presence of specific antiserum to native collagen with specificity of binding reflecting the type of collagen. Binding of denatured and native collagen occur via independent mechanisms.
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PMID:Recongnition by guinea-pig peritoneal exudate cells of conformationally different states of the collagen molecule. 126 53

We performed serologic and synovial investigations in rheumatoid (Latex 1/1280, 1/640, negative and Waaler Rose 1/1024, 1/512, negative), non-rheumatoid and control lots. The immunological results were correlated with ultrastructural changes found in the synovial fluid (SF) at the same titres of rheumatoid factor (RF). The pathologic values of the circulating immune complexes (CIC) (mean = 108.05 U), IgM (mean = 420 UI/ml), IgG (mean = 355.36 UI/ml), and anti-collagen II antibodies (mean = 558.6 U) were present at high titres of RF (Latex 1/1280, Waaler Rose 1/1024). These cases had also major ultrastructural changes of the nucleus and cytoplasm. We inferred from this the implication of the immune factors in the etiology and pathology of the Rheumatoid Arthritis (RA). The high, titres of RF were correlated with pathologic values of the C-reactive-protein (CRP) (mean = 13.31 mg%) and alpha-1-acid glycoprotein (A-1-GA) (mean = 158.3 mg%). The decline of the complement fraction C3 from the synovial fluid in RA confirms the immune character of the rheumatoid synovitis and may be useful in the diagnosis process. The significantly lower concentrations of the protease inhibitors alpha-1-anti-trypsin (A-1-AT) (mean = 165.1 mg%) and alpha-2-macroglobulin (A-2-M) (mean = 129.6 mg%) in synovial fluid suggest a diminution of the anti-proteasic activity due to local immune conflict.
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PMID:Some humoral immunological aspects of the rheumatoid arthritis correlated with the ultrastructural changes of the rheumatoid synovial fluid. 128 62

A human prostate cancer model was established by inoculating a prostate specific antigen (PSA)-producing LNCaP cell line with either prostate or bone fibroblasts. Alternatively, this human prostate cancer model can also be established by inoculating LNCaP cells with growth factor(s) (GFs) and extracellular matrix (ECM) immobilized on Gelfoam. The resulting LNCaP tumors were used to evaluate PSA production and excretion in athymic hosts. This model was also employed to examine the biochemical nature of mesenchymal cell-derived growth-promoting protein(s) and to assess the efficacy of potential chemotherapeutic agents. Because of the propensity of human prostate cancer to metastasize to the bone, this study defined a 1.0 M NaCl-eluted fraction, MS1, from the conditioned medium of a bone stromal cell line (MS) by heparin-affinity column chromatography. The growth-promoting activity was assayed both in vivo (e.g., tumor formation) and in vitro (e.g., soft agar colony formation). We found that the growth-promoting activity was trypsin- and heat-sensitive, and partially degraded by acid and dithiothreitol. Immunochemical studies indicated that the polyclonal antibody raised against MS1 blocked the growth-promoting effect elicited by the bone-conditioned media. This growth-promoting factor was found to be immunochemically dissimilar to KGF, HGF, and bFGF. However, addition of bFGF, HGF and NGF, but not aFGF, TGF beta, IGF1, IGF2, PDGF, EGF, TGF alpha and KGF, stimulated anchorage-independent growth of prostate cells, a condition closely parallel to tumor formation in vivo. We found that the MS1 fraction also contained fibronectin and tenascin but not laminin or collagen IV.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Human prostate cancer model: roles of growth factors and extracellular matrices. 128 80

In vivo, the extracellular matrix modulates the phenotype of the connective tissue cells both through its biochemical composition and the transfer of mechanical information. In this study, the mechanical effect was investigated in collagen gels populated by skin fibroblasts maintained under tension (bound lattices (BL)) compared with free retracting lattices (FL) and monolayer on plastic. The overall proteins and collagen synthesis of human skin fibroblasts, investigated by isotopic labeling, were decreased respectively by a factor of about 20 and 40 in FL compared with monolayers and increased by a factor of 4 and 6 in BL versus FL. As assayed by the degradation of [3H]collagen type I by trypsin-activated medium conditioned by fibroblasts under the three models of culture, collagenase activity was inversely regulated and increased in lattices when compared with monolayer culture. It was four times higher in FL than in BL. The steady-state level of mRNA coding for procollagen types I, III, and VI polypeptides, fibronectin, elastin, beta-actin, and procollagenase was determined by cDNA hybridization. The mRNA coding for beta-actin as well as for the various extracellular matrix macromolecules were increased in BL when compared with FL while the level of procollagenase mRNA was lower. These data demonstrate the existence of a modulation of the function of the fibroblasts performed by mechanical forces. This regulation operates, at least in part, at a pretranslational level.
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PMID:Pretranslational regulation of extracellular matrix macromolecules and collagenase expression in fibroblasts by mechanical forces. 131 27


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