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Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ability of cellular vascular components including endothelial cells, smooth muscle cells, and fibroblasts to interact with the collagenolytic activity of invasive human tumor cell lines has been investigated. The human HT1080 fibrosarcoma and Bowe melanoma cells, which rapidly digest collagenous proteins in vitro, failed to dissolve them when cocultivated with bovine endothelial cells. This inhibition was not dependent on the ability of endothelial cells to form a monolayer separating the tumor cells from the collagenous substrate. In contrast, little collagenolysis inhibitory activity was detected in bovine vascular smooth muscle cells and human fibroblasts when compared to endothelial cells. Serum-free medium conditioned by endothelial cells inhibited tumor cell-mediated collagenolysis. Our data further suggest that this inhibition was mediated by secreted collagenase inhibitors, since endothelial cell-conditioned medium did not suppress the production of metalloproteinases by the tumor cells but inhibited the activities of collagenases derived from tadpole, rabbit, and human fibroblasts. Treatment of the endothelial cells with cycloheximide suppressed the collagenase inhibitory activity, demonstrating active production of collagenase inhibitors by the cells. Gel filtration chromatography of endothelial cell-conditioned medium allowed the separation of two distinct peaks with inhibitory activities for vertebrate collagenase in the molecular weight range of 70,000 to 75,000 and 30,000 to 35,000, respectively. While the inhibitor with an approximate molecular weight of 30,000 to 35,000 shared many properties with the tissue inhibitor of metalloproteinases, the high-molecular-weight inhibitor demonstrated characteristics not yet described for any collagenase inhibitor. The production and secretion of inhibitors of vertebrate collagenase by bovine endothelial cells may be of importance in the local control of collagen turnover under physiological as well as pathological conditions.
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PMID:Inhibition of tumor cell collagenolytic activity by bovine endothelial cells. 370 89

In this review the production of interstitial collagenase in DMBA-induced mammary tumors of the rat has been examined. Cell sorting and cell cultures have given us the opportunity to relate the release of collagenase to a specific cell type. By means of FITC-fluorescence and monospecific antibodies (S. Sakamoto, Harvard University, Boston) it was further possible to localize collagenase in vitro and in vivo. The most outstanding characteristic is that collagenase is produced both by cuboidal, epithelial cell and by macrophages in vitro but not by myoepithelial-like cells. On the other hand, synthesis of collagenase in vivo was detected in some stromal cells, possibly macrophages, but not in neoplastic cuboidal cells. This observation has been related to the inability of cuboidal cells to interact with stromal, fibrillar collagen in vivo since tumor cells are arranged in glandular-like structures bordered by myoepithelial cells and a basement membrane. In vitro, fibrillar rat tail tendon collagen was found to be a potent stimulator of collagenase production by cuboidal cells. Collagenase stimulation by interstitial collagen therefore suggests a plausible mechanism for the degradation of collagen fibrils during local invasion by mammary tumor cells.
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PMID:Biological significance of interstitial collagenase in DMBA-induced mammary tumors of the rat. 609 94

Bovine capillary endothelial cells have been found to respond to several stimuli by producing increased amounts of plasminogen activator and latent collagenase. These stimulators include the tumor promoter tetradecanoyl phorbol-13-acetate as well as crude preparations from a human hepatoma, bovine retinae, and mouse adipocytes, all of which are known to contain angiogenic factors. Endothelial cells and skin fibroblasts do not respond to these stimuli in the same way, indicating a specificity of the response. In addition, inhibitors of plasmin and vertebrate collagenase have been isolated from cartilage, a tissue resistant to neovascularization. We have proposed that these specific protease inhibitors confer on cartilage its antiangiogenic properties.
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PMID:The involvement of proteases and protease inhibitors in neovascularization. 617 34

Cultured bovine capillary endothelial (BCE) cells produce low levels of collagenolytic activity and significant amounts of the serine protease plasminogen activator (PA). When grown in the presence of nanomolar quantities of the tumor promoter 12-O-tetradecanoyl phorbol-13-acetate (TPA), BCE cells produced 5-15 times more collagenolytic activity and 2-10 times more PA than untreated cells. The enhanced production of these enzymes was dependent on the dose of TPA used, with maximal response at 10(-7) to 10(-8) M. Phorbol didecanoate (PDD), an analog of TPA which is an active tumor promoter, also increased protease production. 4-O-methyl-TPA and 4alpha-PDD, two analogs of TPA which are inactive as tumor promoters, had no effect on protease production. Increased PA and collagenase activities were detected within 7.5 and 19 h, respectively, after the addition of TPA. The TPA-stimulated BCE cells synthesized a urokinase-type PA and a typical vertebrate collagenase. BCE cells were compared with bovine aortic endothelial (BAE) cells and bovine embryonic skin (BES) fibroblasts with respect to their production of protease in response to TPA. Under normal growth conditions, low levels of collagenolyic activity were detected in the culture fluids from BCE, BAE, and BES cells. BCE cells produced 5-13 times the basal levels of collagenolytic activity in response to TPA, whereas BAE cells and BES fibroblasts showed a minimal response to TPA. Both BCE and BAE cells exhibited relatively high basal levels of PA, the production of which was stimulated approximately threefold by the addition of TPA. The observation that BCE cells and not BAE cells produced high levels of both PA and collagenase activities in response to TPA demonstrates a significant difference between these two types of endothelial cells and suggests that the enhanced detectable activities are a property unique to bovine capillary and microvessel and endothelial cells.
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PMID:Plasminogen activator and collagenase production by cultured capillary endothelial cells. 618 6

The existing forms of collagenase [EC 3.4.24.7] in the human uterine cervix were examined. The latent collagenase extracted by homogenization in 0.25% Triton X-100 containing 0.01 M CaCl2 was indicated to be a complex of collagenase with alpha 2-macroglobulin by the behavior of the fraction of this enzyme before and after treatment with NaSCN on Sephadex G-150 column chromatography and an immunodiffusion method. The active collagenase was extracted by rehomogenization in 50 mM Tris-HCl buffer, pH 7.4, containing 0.1 M M CaCl2 from the insoluble residue at 0 degrees C. Another latent collagenase was extracted from the insoluble fraction in the same buffer by heating at 60 degrees C for 4 min and this enzyme was activated by 4-aminophenylmercuric acetate or trypsin. The molecular weights of the active and the latent forms were approximately 7.3 x 10(4) and 9.4 x 10(4), respectively. This indicates that the latency is due to the formation of a low molecular weight inhibitor enzyme complex. These results clarified that the human uterine cervix contains three existing forms (alpha 2-macroglobulin complex, active form and low molecular weight inhibitor complex) of collagenase under these experimental conditions.
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PMID:The existing forms of collagenase in the human uterine cervix. 624 99

Latent pig synovial collagenase (EC 3.4.24.7) can be activated by a variety of different treatments to give an active enzyme form of lower molecular weight which rapidly degrades collagen. Trypsin and plasmin effectively activated the latent collagenase whilst elastase and cathepsin G degraded most of the latent enzyme before it was activated. A number of mercurials were compared and maximum activation was achieved using 4-aminophenylmercuric acetate and phenylmercuric chloride. The latent collagenase bound to a mercurial-Sepharose column and was eluted in the active form with NaCl. The latent collagenase also activated spontaneously and the conditions which encouraged and prevented this activation were studied. High NaCl concentration, diisopropylphosphofluoridate, soybean trypsin inhibitor, low Zn2+ concentration and high and low pH all prevented the spontaneous activation of latent pig synovial collagenase.
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PMID:The activation of latent pig synovial collagenase. 626 Feb

Neutral collagenase (EC 3.4.24.7) has been detected in human liver biopsies, baboon liver for the first time. The reaction mixtures were composed of collagen in solution and total liver homogenate in 0.5 M Tris-HCl, pH 7.5 at 25 degree C/0.2 M NaCl/10 mM CaCl2/3 mM p-chloromercuribenzoic acid. Collagenase activity was found by directly subjecting the reaction mixtures to viscometric assay and the activity was confirmed to be due to neutral collagenase by identifying the products using disc gel electrophoresis. It proved necessary to use p-chloromercuribenzoic acid in order to reveal collagenase activity in total liver homogenates from these species. The p-chloromercuribenzoic acid served to inhibit thiol proteinases and all other signs of nonspecific collagenolysis on disc gel electrophoresis, and it was able to activate latent collagenase which trypsin could not.
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PMID:Direct measurement of neutral collagenase activity in homogenates from baboon and human liver. 626 Feb 7

This rapid, sensitive method of determining collagenase (EC 3.4.24.7) activity incorporates several advantages of previous methods. Soluble [14C]acetylated collagen is prepared as the enzyme substrate and collagen-cleavage products are separated from noncleaved collagen by precipitation with dioxane/methanol. The assay is more reproducible than previous methods and has a lower detection limit, 15 mU of enzyme activity. We used the method in a competitive substrate assay with isolated extracellular hepatic matrix from cirrhotic and normal rat liver. Purified collagenase was consistently bound to normal rat matrix to a greater extent than to cirrhotic matrix, suggesting that in hepatic fibrosis the extracellular matrix is not as susceptible to collagenase degradation as that in normal liver.
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PMID:An improved assay of mammalian collagenase activity, and its use to determine hepatic extracellular matrix susceptibility to degradation. 629 Jan 3

Monolayer cultures of rabbit synovial fibroblasts stimulated with phorbol myristate acetate to produce large amounts of collagenase (EC 3.4.24.7) were used to study the biosynthesis and secretion of this enzyme. [3H]Leucine was added to cell cultures for pulse-chase and continuous-labelling experiments. The labelled procollagenase synthesized was identified by immunoprecipitation followed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and fluorography. The amounts of intracellular and extracellular proenzyme were quantified by measuring radioactivity incorporated into the proteins. procollagenase was synthesized as doublet proteins of Mr 57 000 and Mr 61 000. Immunoprecipitable proenzyme proteins were first detected in culture medium 35 min after [3H]leucine was added to the cells. Monensin treatment of the cells inhibited procollagenase secretion and led to intracellular accumulation of the proenzyme. Cells treated with tunicamycin produced only the 57 000-Mr form, indicating that in rabbit synovial cells the 61 000-Mr form was post-translationally modified by addition of oligosaccharides to asparagine residues. The ratios of glycosylated to unglycosylated forms in cell lysates and in culture medium were 0.22:1 and 0.07:1 respectively.
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PMID:Biosynthesis and secretion of procollagenase by rabbit synovial fibroblasts. Inhibition of procollagenase secretion by monensin and evidence for glycosylation of procollagenase. 631 Nov 79

The collagen substrate specificity of rat uterus collagenase was studied as a function of both collagen type and species of substrate origin. For each collagen examined, values for the basic kinetic parameters, Km and Vmax (kcat), were determined on collagen in solution at 25 degrees C. In all cases, Lineweaver-Burk plots were linear and rat uterus collagenase behaved as a normal Michaelis-Menten enzyme. Collagen types I, II, and III of all species tested were degraded by rat uterus collagenase. Collagen types IV and V were resistant to enzymatic attack. Both enzyme-substrate affinity and catalytic rates were very similar for all susceptible collagens (types I-III). Values for Km ranged from 0.9 to 2.5 X 10(-6) M. Values for kcat varied from 10.7 to 28.1 h-1. The homologous rat type I collagen was no better a substrate than the other animal species type I collagens. The ability of rat uterus collagenase to degrade collagen types I, II, and III with essentially the same catalytic efficiency is unlike the action of human skin fibroblast collagenase or any other interstitial collagenase reported to date. The action of rat uterus collagenase on type I collagen was compared to that of human skin fibroblast collagenase, with regard to their capacity to cleave collagen as solution monomers versus insoluble fibrils. Both enzymes had essentially equal values for kcat on monomeric collagen, yet the specific activity of the rat uterus collagenase was 3- to 6-fold greater on collagen fibrils than the skin fibroblast enzyme. Thus, in spite of their similar activity on collagen monomers in solution, the rat uterus collagenase can degrade collagen aggregated into fibrils considerably more readily than can human skin fibroblast collagenase.
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PMID:The collagen substrate specificity of rat uterus collagenase. 631 21


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