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)

An inhibitor of coagulation factor XIa was purified from serum-free conditioned medium of HepG2 liver cells. Platelets stimulated with thrombin or calcium ionophore (A23187) secrete a protein functionally and immunologically identical to the inhibitor, implying a role for this inhibitor in hemostasis. Analysis of the amino-terminal amino acid sequence and immunologic reactivity showed the inhibitor to be a truncated form of the Alzheimer's amyloid precursor protein that contains a Kunitz-type serine protease inhibitor domain and at least a portion of the amyloid beta protein. It inhibits factor XIa and trypsin with a Ki of 450 +/- 50 pM and 20 +/- 10 pM, respectively. Heparin (1 unit/ml) did not significantly effect inhibition of trypsin, but inhibition of XIa was 15 times greater (Ki = 25 +/- 15 pM) in the presence of heparin.
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PMID:Platelet coagulation factor XIa-inhibitor, a form of Alzheimer amyloid precursor protein. 211 85

Tissue factor pathway inhibitor-2 (TFPI-2)/matrix-associated serine protease inhibitor (MSPI), a 32- to 33-kDa Kunitz-type serine protease inhibitor, inhibits plasmin and trypsin. Because plasmin and trypsin are involved in the activation of promatrix metalloproteases proMMP-1 and proMMP-3, we investigated the role of TFPI-2/MSPI in the activation of these proenzymes. Both plasmin and trypsin activated proMMP-1 by converting the 53-kDa proenzyme to the partially active 43-kDa polypeptide; this activity was inhibited by TFPI-2/MSPI. Similarly, TFPI-2/MSPI inhibited the conversion of 66-kDa proMMP-3 to the activated 45- and 30-kDa polypeptides by plasmin and trypsin. Because plasmin is involved in the physiological activation of proMMP-3, we tested whether TFPI-2/MSPI inhibits the activation of proMMP-3 by HT-1080 fibrosarcoma cells and urokinase-charged HeLa cells. We found that the inhibitor inhibited proMMP-3 activation by HT-1080 cells and urokinase-charged HeLa cells. Collectively, our results suggest that TFPI-2/MSPI indirectly regulates MMP-1- and MMP-3-catalyzed matrix proteolysis by regulating the activation of proMMP-1 and proMMP-3.
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PMID:Regulation of ProMMP-1 and ProMMP-3 activation by tissue factor pathway inhibitor-2/matrix-associated serine protease inhibitor. 1008 61

Human tissue factor pathway inhibitor-2 (TFPI-2)/matrix-associated serine protease inhibitor (MSPI), a Kunitz-type serine protease inhibitor, inhibits plasmin, trypsin, chymotrypsin, plasma kallikrein, cathepsin G, and factor VIIa-tissue factor complex. The mature protein has a molecular mass of 32-33 kDa, but exists in vivo as two smaller, underglycosylated species of 31 and 27 kDa. TFPI-2/MSPI triplet is synthesized and secreted by a variety of cell types that include epithelial, endothelial, and mesenchymal cells. Because the majority (75-90%) of TFPI-2/MSPI is associated with the extracellular matrix (ECM), we examined which components of the ECM bind TFPI-2/MSPI. We found that TFPI-2/MSPI bound specifically to heparin and dermatan sulfate. Interaction of these two glycosaminoglycans (GAGs) with TFPI-2/MSPI involved one or more common protein domains, as evidenced by cross-competition experiments. However, binding affinity for TFPI-2/MSPI with heparin was 250-300 times greater than that for TFPI-2/MSPI with dermatan sulfate. Binding of TFPI-2/MSPI to GAGs was inhibited by NaCl or arginine but not by glucose, mannose, galactose, 6-aminohexanoic acid, or urea, suggesting that arginine-mediated ionic interactions participate in the GAG binding of TFPI-2/MSPI. This supposition was supported by the observation that only NaCl or arginine could elute the TFPI-2/MSPI protein triplet from an ECM derived from human dermal fibroblasts. Reduced TFPI-2/MSPI did not bind to heparin, suggesting that proper disulfide pairings and conformation are essential for matrix binding. To determine whether heparin modulates the activity of TFPI-2/MSPI, we determined the rate of inhibition of plasmin by the inhibitor with and without heparin and found that TFPI-2/MSPI is more active in the presence of heparin. Collectively, our results demonstrate that conformation-dependent arginine-mediated ionic interactions are responsible for the TFPI-2/MSPI triplet binding to fibroblast ECM, heparin, and dermatan sulfate and that heparin augmented the rate of inhibition of plasmin by TFPI-2/MSPI.
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PMID:Matrix localization of tissue factor pathway inhibitor-2/matrix-associated serine protease inhibitor (TFPI-2/MSPI) involves arginine-mediated ionic interactions with heparin and dermatan sulfate: heparin accelerates the activity of TFPI-2/MSPI toward plasmin. 1049 84

Protease inhibitors regulate a variety of physiological and pathological processes including angiogenesis, embryo implantation, intravascular fibrinolysis, wound healing, and tumor invasion. Tissue factor pathway inhibitor (TFPI) 2 is a Mr 32,000 Kunitz-type serine protease inhibitor that inhibits plasmin, trypsin, chymotrypsin, cathepsin G, and plasma kallikrein but not urokinase-type plasminogen activator, tissue plasminogen activator, or thrombin. In this study, we determined the relative amounts of TFPI-2 in low-, intermediate-, and high-grade human glioma cell lines and tumor tissue samples. TFPI-2 protein and mRNA levels (measured by Western and Northern blotting) were highest in low-grade glioma cells (Hs683), lower in anaplastic astrocytoma cells (SW1088 and SW1783), and undetectable in high-grade glioma cells (SNB19). Analysis of TFPI-2 protein in human normal brain and in glioma tumor tissues for TFPI-2 revealed the highest levels in normal brain, lesser amounts in low-grade gliomas and anaplastic astrocytomas, and undetectable amounts in glioblastomas. In situ hybridization of TFPI-2 mRNA with normal brain tissues revealed the greatest positivity in neurons, with moderate positivity in both glial and endothelial cells and moderate, little, or no TFPI-2 mRNA in low-grade glioma, anaplastic astrocytoma, and glioblastoma tumor tissue samples, respectively. We also found that recombinant TFPI-2 inhibited the invasiveness of SNB19 glioblastoma cells in a Matrigel assay in a dose-dependent manner. Collectively, these results suggest that TFPI-2 has a regulatory role in the invasiveness of gliomas in vitro and in vivo.
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PMID:Expression of tissue factor pathway inhibitor 2 inversely correlates during the progression of human gliomas. 1129 50

Human tissue factor pathway inhibitor-2 (TFPI-2) is a Kunitz-type serine protease inhibitor that inhibits plasmin, trypsin, chymotrypsin, cathepsin G and plasma kallikrein but not urokinase (uPA) or tissue-type plasminogen activator and thrombin. Earlier studies from our and other laboratories have shown that the production of TFPI-2 is downregulated during the progression of various cancers. To investigate the role of TFPI-2 in the invasion and metastasis of lung tumors, the human lung cancer cell line A549, which produces high levels of TFPI-2, was stably transfected with a vector capable of expressing an antisense transcript complementary to the full-length TFPI-2 mRNA. Northern blot analysis was used to quantify the TFPI-2 mRNA transcript, and western blot analysis was used to measure TFPI-2 protein levels in parental cells and stably transfected (vector and antisense) clones. The levels of TFPI-2 mRNA and protein were significantly less in antisense clones than in the parental and vector controls. The invasive potential of the parental cells and stably transfected vector clones in vitro, as measured by the Matrigel invasion assay, was also markedly less than that of antisense clones. Further characterization of these clones showed that more cells migrated from antisense clones than from parental and vector clones. These data suggest that TFPI-2 is critical for the invasion and metastasis of lung cancer and that the downregulation of TFPI-2 production may be a feasible approach to increase invasiveness and metastasis.
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PMID:In vitro modulation of human lung cancer cell line invasiveness by antisense cDNA of tissue factor pathway inhibitor-2. 1131 97

To test the hypothesis that Na+ transport in human bronchial epithelial (HBE) cells is regulated by a protease-mediated mechanism, we investigated the effects of BAY 39-9437, a recombinant Kunitz-type serine protease inhibitor, on amiloride-sensitive short-circuit current of normal [non-cystic fibrosis (CF) cells] and CF HBE cells. Mucosal treatment of non-CF and CF HBE cells with BAY 39-9437 decreased the short-circuit current, with a half-life of approximately 45 min. At 90 min, BAY 39-9437 (470 nM) reduced Na+ transport by approximately 70%. The inhibitory effect of BAY 39-9437 was concentration dependent, with a half-maximal inhibitory concentration of approximately 25 nM. Na+ transport was restored to control levels, with a half-life of approximately 15 min, on washout of BAY 39-9437. In addition, trypsin (1 microM) rapidly reversed the inhibitory effect of BAY 39-9437. These data indicate that Na+ transport in HBE cells is activated by a BAY 39-9437-inhibitable, endogenously expressed serine protease. BAY 39-9437 inhibition of this serine protease maybe of therapeutic potential for the treatment of Na+ hyperabsorption in CF.
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PMID:Na+ transport in normal and CF human bronchial epithelial cells is inhibited by BAY 39-9437. 1140 39

Human tissue factor pathway inhibitor-2 (TFPI-2) is a Kunitz-type serine protease inhibitor that inhibits plasmin, trypsin, chymotrypsin, cathepsin G, and plasma kallikrein but not urokinase-type plasminogen activator, tissue plasminogen activator, or thrombin. Preliminary findings in our laboratory suggested that the expression of TFPI-2 is downregulated or lost during tumor progression in human gliomas. To investigate the role of TFPI-2 in the invasiveness of brain tumors, we stably transfected the human high-grade glioma cell line SNB19 and the human low-grade glioma cell line Hs683 with a vector capable of expressing a transcript complementary to the full-length TFPI-2 mRNA in either sense (0.7 kb) or antisense (1 kb) orientations. Parental cells and stably transfected cell lines were analysed for TFPI-2 protein by Western blotting and for TFPI-2 mRNA by Northern blotting. The levels of TFPI-2 protein and mRNA were higher in the sense clones (SNB19) and decreased in the antisense (Hs683) clones than in the corresponding parental and vector controls. In spheroid and matrigel invasion assays, the SNB19 parental cells were highly invasive, but the sense-transfected SNB-19 clones were much less invasive; the antisense-transfected Hs683 clones were more invasive than their parental and vector controls. After intracerebral injection in mice, the sense-transfected SNB19 clones were less able to form tumors than were their parental and vector controls, and the antisense-Hs683 clones but not the parental or vector controls formed small tumors. This is the first study to demonstrate that down- or upregulation of TFPI-2 plays a significant role in the invasive behavior of human gliomas.
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PMID:A novel function of tissue factor pathway inhibitor-2 (TFPI-2) in human glioma invasion. 1168 73

Hepatocyte growth factor activator inhibitor type 1 (HAI-1) is a Kunitz-type serine protease inhibitor identified as a strong inhibitor of hepatocyte growth factor (HGF) activator and matriptase. HAI-1 is first produced in a membrane-integrated form with two Kunitz domains in its extracellular region, and subsequent ectodomain shedding releases two major secreted forms, one with a single Kunitz domain and one with two Kunitz domains. To determine the roles of the Kunitz domains in the inhibitory activity of HAI-1 against serine proteases, we constructed various HAI-1 mutant proteins and examined their inhibitory activity against HGF activator and trypsin. The N-terminal Kunitz domain (Kunitz I) had potent inhibitory activity against both HGF activator and trypsin, whereas the C-terminal Kunitz domain (Kunitz II) had only very weak inhibitory activity against HGF activator, although its potency against trypsin was equivalent to that of Kunitz I. These results indicate that Kunitz I is the functional domain of HAI-1 for inhibiting the HGF-converting activity of HGF activator. Furthermore, the presence of two Kunitz domains affected the inhibitory activity of HAI-1 against HGF activator, and it showed a similar, but not additive, level of inhibitory activity against trypsin when compared with that of the individual Kunitz domains. These results suggest that serine protease binding sites of Kunitz I and Kunitz II are located close to each other and that proteolytic processing to generate HAI-1 with only one Kunitz domain regulates the activity of HAI-1.
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PMID:Functional characterization of Kunitz domains in hepatocyte growth factor activator inhibitor type 1. 1180 18

Textilinin-1 (Txln-1), a Kunitz-type serine protease inhibitor, is a 59-amino-acid polypeptide isolated from the venom of the Australian Common Brown snake Pseudonaja textilis textilis. This molecule has been suggested as an alternative to aprotinin, also a Kunitz-type serine protease inhibitor, for use as an anti-bleeding agent in surgical procedures. Txln-1 shares only 47% amino-acid identity to aprotinin; however, six cysteine residues in the two peptides are in conserved locations. It is therefore expected that the overall fold of these molecules is similar but that they have contrasting surface features. Here, the crystallization of recombinant textilinin-1 (rTxln-1) as the free molecule and in complex with bovine trypsin (229 amino acids) is reported. Two organic solvents, phenol and 1,4-butanediol, were used as additives to facilitate the crystallization of free rTxln-1. Crystals of the rTxln-1-bovine trypsin complex diffracted to 2.0 angstroms resolution, while crystals of free rTxln-1 diffracted to 1.63 angstroms resolution.
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PMID:Crystallization and preliminary X-ray analysis of a Kunitz-type inhibitor, textilinin-1 from Pseudonaja textilis textilis. 1682 Jun 82

Recent investigations point to an important role for peptidases in regulating transcellular ion transport by the epithelial Na(+) channel, ENaC. Several peptidases, including furins and proteasomal hydrolases, modulate ENaC maturation and disposal. More idiosyncratically, apical Na(+) transport by ENaC in polarized epithelia of kidney, airway, and gut is stimulated constitutively by one or more trypsin-family serine peptidases, as revealed by inhibition of amiloride-sensitive Na(+) transport by broad-spectrum antipeptidases, including aprotinin and bikunin/SPINT2. In vitro, the transporting activity of aprotinin-suppressed ENaC can be restored by exposure to trypsin. The prototypical channel-activating peptidase (CAP) is a type 1 membrane-anchored tryptic peptidase first identified in Xenopus kidney cells. Frog CAP1 strongly upregulates Na(+) transport when coexpressed with ENaC in oocytes. The amphibian enzyme's apparent mammalian orthologue is prostasin, otherwise known as CAP1, which is coexpressed with ENaC in a variety of epithelia. In airway cells, prostasin is the major basal regulator of ENaC activity, as suggested by inhibition and knockdown experiments. Other candidate regulators of mature ENaC include CAP2/TMPRSS4 and CAP3/matriptase (also known as membrane-type serine protease 1/ST14). Mammalian CAPs are potential targets for treatment of ENaC-mediated Na(+) hyperabsorption by the airway in cystic fibrosis (CF) and by the kidney in hypertension. CAPs can be important for mammalian development, as indicated by embryonic lethality in mice with null mutations of CAP1/prostasin. Mice with selectively knocked out expression of CAP1/prostasin in the epidermis and mice with globally knocked out expression of CAP3/matriptase exhibit phenotypically similar defects in skin barrier function and neonatal death from dehydration. In rats, transgenic overexpression of human prostasin disturbs salt balance and causes hypertension. Thus, several converging lines of evidence indicate that ENaC function is regulated by peptidases, and that such regulation is critical for embryonic development and adult function of organs such as skin, kidney, and lung.
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PMID:Regulation of the epithelial Na+ channel by peptidases. 1733 14


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