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)

EDTA inhibitable type IV collagenolytic activity copurified with laminin preparations from the Engelbreth-Holm-Swarm (EHS) tumor. Several gelatinolytic and type IV collagenolytic matrix metalloproteinase (MMP) species were visualized in EHS laminin from three different sources by gelatin and type IV collagen substrate gel electrophoresis. Incubation with 4-aminophenylmercuric acetate and trypsin suggested that laminin contained both active and latent MMPs. EHS-derived reconstituted basement membrane, Matrigel, was found to possess an MMP profile identical to that of laminin. The presence of 72-kDa (MMP-2) and 92-kDa (MMP-9) gelatinases/type IV collagenases was demonstrated in laminin and Matrigel preparations by Western blot analysis. A rough quantitation of MMP-2 and MMP-9 in 30 micrograms of laminin and 100 micrograms of Matrigel was between 0.3 and 0.6 ng. The presence of these contaminants must be considered in experiments addressing the effects of EHS laminin or Matrigel on cell behavior and, in particular, stimulation of cellular proteolytic activity.
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PMID:Identification of the 72-kDa (MMP-2) and 92-kDa (MMP-9) gelatinase/type IV collagenase in preparations of laminin and Matrigel. 829 37

The putative matrix metalloproteinase mouse stromelysin-3 was expressed from Escherichia coli and from a mouse myeloma cell line. In the former case a single major protein of 58-kDa was detectable by immunoblotting, but no proteolytic activity could be elicited by zymography or trypsin or organomercurial treatment as would be expected for a typical matrix metalloproteinase. In the latter case immunodetectable proteins of 55-58 and 27-28-kDa were produced. The effect of trypsin or organomercurial treatment of the 55-58-kDa forms was to generate a 51-kDa form and lower molecular mass fragments. Upon zymographic analysis only the 27-28-kDa forms showed caseinolytic activity. N-terminal sequencing and immunoblotting analysis with antibodies specific to distinct domains of stromelysin-3 indicated that the 27-28-Da stromelysin-3 forms had lost the predicted propeptide and the majority of the C-terminal domain. The purified 28-kDa form of stromelysin-3 could weakly degrade a number of extracellular matrix proteins and was inhibited by TIMP. However, the evidence that mature full-length stromelysin-3 is a metalloproteinase could not be substantiated and the precise role of this protein in vivo remains to be elucidated. By partial analogy with interstitial collagenase, one hypothesis is that stromelysin-3 with an intact C-terminal domain has specific properties for an as yet undefined substrate.
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PMID:The 28-kDa N-terminal domain of mouse stromelysin-3 has the general properties of a weak metalloproteinase. 834 Mar 72

Gelatinolytic metalloproteinases implicated in connective tissue remodeling and tumor invasion are secreted from several types of cells in the form of inactive zymogens. In this report, characterization of gelatinase activity secreted by the BR line of dog mastocytoma cells reveals a phorbol-inducible, approximately 92-kD, Ca2+ - and Zn2+ -dependent proenzyme cleaved over time to smaller, active forms. Incubation of cells with the general serine protease inhibitor, PMSF, prevented proenzyme cleavage and permitted its purification free of activation products. The NH2-terminal 13 amino acids of the purified mastocytoma progelatinase are 50-67% identical to those of human, mouse, and rabbit 92-kD progelatinase (gelatinase B; matrix metalloproteinase-9). Degranulation of mastocytoma cells using ionophore A23187 greatly accelerated proenzyme cleavage, suggesting that a serine protease present in secretory granules hydrolyzed the progelatinase to active fragments. To identify the activating protease, cells were coincubated with ionophore and a panel of selective serine protease inhibitors. Soybean trypsin inhibitor and succinyl-L-Ala-Ala-Pro-Phe-chloromethylketone, which inhibit mast cell chymase, prevented progelatinase activation. Inhibitors of tryptase and dog mast cell protease (dMCP)-3, i.e., aprotinin or bis(5-amidino-2-benzimidazolyl) methane (BABIM), did not. In further experiments using highly purified enzymes, mastocytoma cell chymase activated 92-kD progelatinase in the absence of other enzymes or cofactors; tryptase and dMCP-3, however, had no effect. These data demonstrate that dog mastocytoma cells secrete a metalloproteinase related to progelatinase B that is directly activated outside of the cell by exocytosed chymase, and provide the first demonstration of a cell that activates a matrix metalloproteinase it secretes by cosecreting an activating enzyme. In mastocytomas, this pathway may facilitate tumor invasion of surrounding tissues, and in normal mast cells, it could play a role in tissue remodeling and repair.
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PMID:Dog mastocytoma cells secrete a 92-kD gelatinase activated extracellularly by mast cell chymase. 860 22

It has been proposed that the cell-mediated activation of progelatinase A requires binding of the C-terminal domain of the proenzyme to a membrane-associated complex of the membrane type matrix metalloproteinase MT1-MMP and TIMP-2. Subsequent sequential proteolysis of the propeptide by MT1-MMP and gelatinase A is thought to generate the active form of gelatinase A. We have prepared the proform of the catalytic domain of the MT1-MMP and demonstrated that this may be activated in vitro by trypsin proteolysis to yield a functional proteinase capable of cleaving typical metalloproteinase peptide substrates, gelatin and casein. The active catalytic domain of MT1-MMP was also shown to activate progelatinase A to a fully active form. Using the inactive mutant pro-E375A gelatinase A, we dissected the propeptide processing events that occur. MT1-MMP cleaves the propeptide at the sequence Asn37-Leu38 only. Further cleavage of the mutant enzyme propeptide at Asn80-Tyr81, equivalent to that of the active wild type gelatinase A, could only be effected by addition of gelatinase A to the system. TIMP-1 was essentially unable to prevent MT1-MMP processing of wild type or E375A progelatinase A, whereas TIMP-2 and TIMP-3 were good inhibitors of these events. Analysis of the rate of binding of TIMPs to the catalytic domain of MT1-MMP using kinetic methods showed that TIMP-1 is an extremely poor inhibitor of MT1-MMP. In comparison, TIMP-2 and TIMP-3 are excellent inhibitors, binding more rapidly to the catalytic domain of MT1-MMP than to the catalytic domain of gelatinase A. These data demonstrate the basic mechanism of MT1-MMP action on progelatinase A and the reason for the lack of inhibition by TIMP-1 previously demonstrated in cell-based activation studies.
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PMID:The soluble catalytic domain of membrane type 1 matrix metalloproteinase cleaves the propeptide of progelatinase A and initiates autoproteolytic activation. Regulation by TIMP-2 and TIMP-3. 866 32

92-kDa type IV collagenase/gelatinase (matrix metalloproteinase-9; MMP-9; gelatinase B) expression and secretion has been shown to correlate with the invasive and metastatic potential of various malignant cells. MMP activity is tightly controlled by specific tissue inhibitors of metalloproteinases (TIMPs). We found the leukemic cell line HL-60 constitutively to release a 94-kDa gelatinase which we identified as MMP-9 shortened by nine amino acids at its N-terminal end. An additional gelatinolytic activity was present in small amounts and identified as a 63-kDa fragment of MMP-9 generated by autocatalytical processing. Both enzymes were identical regarding their N-terminus, indicating C-terminal truncation for the former. Incubation of cells with phorbol ester resulted in elevated amounts of both enzymes in conditioned media and in the secretion of TIMP-1. Both gelatinases were shown to be activated by trypsin and organomercurials and to possess similar activities towards various substrates. However, the 63-kDa enzyme differed from the 94-kDa enzyme in a significantly reduced inhibition by recombinant TIMP-1 and TIMP-2. Thus, the 63-kDa fragment of MMP-9 once activated may escape the regulatory influence of its specific inhibitors and may thereby promote matrix degradation during invasion of leukemic cells.
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PMID:HL-60 leukemia cells produce an autocatalytically truncated form of matrix metalloproteinase-9 with impaired sensitivity to inhibition by tissue inhibitors of metalloproteinases. 875 73

Activation of matrix metalloproteinase (MMP)-2, the 72-kd collagenase IV/gelatinase A, is involved in extracellular matrix remodeling. It has been suggested that a membrane-type MMP (MT-MMP-1) and the tissue inhibitor of metalloproteinase (TIMP)-2 are involved in MMP-2 processing, but the exact mechanism(s) of its activation remains unclear. We have investigated the role of cell-cell cooperation in the activation of pro-MMP-2 in the liver, using pure cultures and co-cultures of hepatocytes and hepatic stellate cells (HSCs). Northern blot analysis and in situ hybridization showed that, in both pure and co-cultures, HSCs, but not hepatocytes, expressed MMP-2, TIMP-2, and MT-MMP-1 mRNA. Zymography analyses revealed the latent form of MMP-2 in medium from 2-day-old pure HSC cultures with higher amounts in medium from hepatocyte/HSC co-cultures. When hepatocytes were added to 10-day-old HSC cultures, the activated form of MMP-2 was detected, concomitantly with the deposition of an abundant extracellular matrix. Incubation of plasma membrane-enriched fractions from hepatocytes with conditioned medium from pure HSC cultures generated the activated species of MMP-2 (62 and 59 kd). Activation of pro-MMP-2 by hepatocyte membranes was inhibited by EDTA, heat, and trypsin but not by serine proteinase inhibitors. These data show that the co-expression of TIMP-2, MMP-2, and MT-MMP-1 by HSCs does not lead to secretion of the activated form of MMP-2. Hepatocytes, which do not express MMP-2, TIMP-2, or MT-MMP-1, induce MMP-2 activation through a plasma membrane-dependent mechanism(s), thus suggesting that cell-cell interactions are involved in this process in vivo.
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PMID:Activation of matrix metalloproteinase-2 from hepatic stellate cells requires interactions with hepatocytes. 900 21

Increased production of proteinases, such as matrix metalloproteinases (MMPs), is a characteristic feature of malignant tumors. Some human cancers and cell lines derived from them also express trypsinogen, but the function of the extrapancreatic trypsin has remained unclear. In this study we cloned and sequenced trypsinogen-2 cDNA from human COLO 205 colon carcinoma cells and characterized the ability of the enzyme to activate latent human type IV procollagenases (proMMP-2 and proMMP-9). As shown by cloning and N-terminal amino acid sequencing, the amino acid sequence of tumor-associated trypsin-2 is identical to that of pancreatic trypsin-2. We found that both pancreatic trypsin-2 and tumor cell-derived trypsin-2 are efficient activators of proMMP-9 and are capable of activating proMMP-9 at a molar ratio of 1:1000, the lowest reported so far. Human trypsin-2 was a more efficient activator than widely used bovine trypsin and converted the 92-kDa proMMP-9 to a single 77-kDa product that was not fragmented further. The single peptide bond cleaved by trypsin-2 in proMMP-9 was Arg87-Phe88. The generation of the 77-kDa species coincided with the increase in specific activity of MMP-9. In contrast, trypsin-2 only partially activated proMMP-2. Trypsin-2 cleaved the Arg99-Lys100 peptide bond of proMMP-2 generating 62-65-kDa MMP-2 species. Trypsin-2-induced proMMP-2 and -9 conversions were inhibited by tumor-associated trypsin inhibitor added either prior to or during activation indicating that proMMPs were not activated autocatalytically. Trypsin-2 also activated proMMPs associated with tissue inhibitor of matrix metalloproteinases, the complexes of which are thought to be the major MMP forms in vivo. The ability of human tumor cell-derived trypsin-2 to activate latent MMPs suggests a role for trypsin-2 in initiating the proteinase cascade that mediates tumor invasion and metastasis formation.
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PMID:Activation of type IV procollagenases by human tumor-associated trypsin-2. 926 Nov 9

Type II pneumocytes are multifunctional alveolar epithelial cells that play a major role in the maintenance of lung structure and function. Recent evidence supports that these cells can synthesize a variety of extracellular matrix components in vitro, suggesting an active participation in connective tissue remodeling. However, their possible role in extracellular matrix degradation is unknown. In this study the production of matrix metalloproteinases (MMPs) was examined in primary cultures of rat alveolar type II pneumocytes after 2 and 7 days in culture. Under basal conditions, at both periods type II cells expressed interstitial collagenase mRNA. The immunoreactive protein was detected both in the cells and in conditioned media, and collagenolytic activity was revealed after trypsin activation. Gelatinolytic activity was detected by zymography showing a relative molecular mass of approximately 72 and 92 kDa (gelatinases A and B). Phorbol treatment increased collagenase and gelatinase activities. In addition, three alveolar epithelial cell lines were analysed for MMP production: MLE-12 (mice), L2 (rat), and A549 (human). The cell lines A549 and MLE-12 revealed collagenase and gelatinase A and B activities whereas the L2 cell line only exhibited gelatinase A activity, even after PMA induction. These findings demonstrate that alveolar epithelial cells synthesize in vitro several MMPs that confer on them the ability to degrade extracellular matrix and basement membrane components, a capacity of considerable importance for the remodeling of the stromal/epithelial interface.
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PMID:Lung alveolar epithelial cells synthesize interstitial collagenase and gelatinases A and B in vitro. 930 5

We attempted to study the possible relationships between neutrophil-type procollagenase/pro-matrix metalloproteinase (MMP-8) and the serine proteinases plasmin, cathepsin G and tryptase in bronchiectasis. The presence of the plasmin/plasminogen system and plasmin-, cathepsin G- and tryptase-like activities were compared to the activity of endogenously activated MMP-8 in bronchoalveolar lavage (BAL) fluid in 38 bronchiectasis patients and in 14 healthy controls by means of immunohistochemistry, Western-blot and substrate-based functional assays. In contrast to cathepsin G- and tryptase-like activities, the plasmin/plasminogen activator system in BAL fluid was observed to have a relatively weak activation stage and no correlation with disease severity. Neither plasmin-like activities nor concentrations of plasminogen activators from the bronchiectatic patients differed significantly from the values of healthy controls. Immunolocation of plasminogen activator inhibitor-1 showed a marked, but not significant, increase in bronchiectatic lung as compared to controls. In contrast to cathepsin G- and tryptase-like activities, with their strong and significant correlation with endogenously activated collagenase (r=0.9; p=0.0001; and r=0.6; p=0.03, respectively), no correlations were observed between plasmin-like and endogenously activated collagenase (r=0.3; p=0.2) in bronchiectasis. These findings suggest that cathepsin G- and tryptase-like activities may act as potent pro-matrix metalloproteinase-8 activators in patients with bronchiectasis, whereas the plasminogen activator/plasmin cascade was shown to be down-regulated.
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PMID:Potentiative effects of neutral proteinases in an inflamed lung: relationship of neutrophil procollagenase (proMMP-8) to plasmin, cathepsin G and tryptase in bronchiectasis in vivo. 949 62

A bifunctional alpha-amylase/subtilisin inhibitor (RASI) was purified to electrophoretic homogeneity from rice (Oryza sativa L.) bran. Its molecular mass was 21 kDa by SDS-PAGE and its isoelectric point was 9.05. Purified RASI inhibited subtilisin Carlsberg strongly and inhibited alpha-amylase from germinating rice seeds weakly. It inhibited rice alpha-amylase more than barley alpha-amylase, and the inhibition of rice alpha-amylase was greater at higher pHs. RASI did not inhibit trypsin, chymotrypsin, cucumisin, or mammalian alpha-amylase. The RASI was in the outermost part of the rice grain and its subcellular site seemed to be aleurone particles in aleurone cells. SDS-PAGE and western blotting showed that RASI was synthesized in the late milky stage in developing seeds, and it remained fairly constant during the first 7 days of germination.
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PMID:Rice bifunctional alpha-amylase/subtilisin inhibitor: characterization, localization, and changes in developing and germinating seeds. 964 30


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