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:3.4.21.7 (plasmin)
9,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Polymorphonuclear leucocyte (PMN) accumulation is associated with damage to airways epithelial cells in bronchitis, bronchiectasis and some forms of asthma. PMNs release several molecules which may mediate this damage, particularly proteases and oxidants. Using an in vitro model of intact human amnionic epithelial cells (EC) attached to native basement membrane (BM), we evaluated the capacity of several proteases and oxidants to induce detachment of EC from the BM. Maximum desquamation was observed with collagenase, elastase and trypsin, with minimum effective concentrations required to produce 50% EC-desquamation (MEC50) for highly purified collagenase, pancreatic elastase, human leucocyte elastase, human leucocyte cathepsin-G (Cath-G), trypsin, and kallikrein being 3616 +/- 989 U/mL, 32.3 +/- 14.7 U/mL, 85.8 +/- 26.7 U/mL, 360 +/- 20 U/mL, 340 +/- 49 BAEE U/mL and 300 +/- 23 U/mL, respectively. Urokinase (20 U/mL) and plasmin (500 U/mL) produced no desquamation in this system. Relatively high concentrations of oxidants also produced detachment (MEC50 for H2O2 and HOCl being 0.59 +/- 0.006 mol/L and 0.015 +/- 0.009 mol/L, respectively) and pretreatment of EC membranes with non-detaching concentrations of H2O2 rendered them 10-fold more susceptible to protease-induced desquamation, suggesting synergism. Reduced glutathione (GSH), N-acetyl cysteine (NAC), ethylenediamine tetra-acetic acid (EDTA) and 1,10 phenanthroline ablated collagenase induced EC-detachment. Elastase induced detachment was sensitive to inhibition by phenyl methyl sulfonyl fluoride (PMSF) and alpha 1-anti-proteinase (alpha 1-AP) and, to a lesser extent by aprotinin; trypsin-induced detachment was ablated by PMSF, alpha 1-AP and soybean trypsin inhibitor (SBTI) but not by 1,10 phenanthroline or EDTA. Cath-G induced detachment was profoundly inhibited by SBTI, GSH and NAC. These data demonstrate that human EC can be detached from intact BM by several PMN products, including collagenase, Cath-G and elastase, and that PMN-mediated detachment can be prevented by Cath-G and collagenase inhibitors. The data suggest a role for proteases, particularly Cath-G and collagenase, plus oxidants in synergism with proteases, in mediating PMN-induced EC detachment.
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PMID:Study of human epithelial cell detachment and damage: effects of proteases and oxidants. 220 Jul 49

The synthesis of two lysylfluoromethanes is described by an extension of the synthesis method of Rauber, Angliker, Walker & Shaw [(1986) Biochem. J. 239, 633-640]. Ala-Phe-Lys-CH2F was found to be an active-centre-directed inhibitor of plasmin and trypsin, as is the corresponding chloromethane. However, the rate of covalent-bond formation is about an order of magnitude lower at 25 degrees C for the fluoro derivative. It was, in addition, an extremely effective inactivator of cathepsin B at pH 5.4 and 6.4. The chemical reactivity of fluoromethanes was compared with that of chloromethanes as alkylators of GSH. At pH 7.4 and 37 degrees C, a fluoromethane has 1/500th the reactivity of a chloromethane. A comparison of the rates of reaction of the fluoromethane with cathepsin B and with GSH at pH 6.4 revealed an enhancement of 10(8)-fold for the alkylation of the enzyme, ascribable largely to a proximity effect.
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PMID:The synthesis of lysylfluoromethanes and their properties as inhibitors of trypsin, plasmin and cathepsin B. 295 36

We have created a novel thrombolytic agent by the combination of mutation with partial deletion of tissue-type plasminogen activator (t-PA). We constructed Escherichia coli expression vectors for (i) native t-PA (nt-PA) and its derivatives; (ii) K1K2P, consisting of kringle 1 (K1), kringle 2 (K2), and protease (P) domains; (iii) K2P, consisting of K2 and P domains; (iv) D-nt-PA; (v) D-K1K2P; and (vi) D-K2P. The latter three are point mutants of nt-PA, K1K2P, and K2P, respectively, in which Arg275 (number corresponds to that of nt-PA) has been mutated to Asp. The production of nt-PA and its derivatives was remarkably improved by (i) removal of the 3' noncoding region of nt-PA cDNA from expression vectors and (ii) expression in mutant E. coli derived from E. coli HB101, which is insensitive to heat-shock inductions. The proteins produced were precipitated as insoluble aggregates in the cells and were renatured to active forms by extraction with 8 M urea followed by dialysis against a redox buffer containing GSH and GSSG. The renaturation yield depended on the pH of the buffer and the number of disulfide bonds of the proteins (nt-PA << K1K2P < K2P). The mutation of Arg275 (the plasmin cleavage site) caused an increase in the catalytic enhancement by fibrin and a decrease of the interaction with plasminogen activator inhibitors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Production and characterization of a novel tissue-type plasminogen activator derivative in Escherichia coli. 776 73

Hepatic veno-occlusive disease (VOD) of the liver is a common complication following high-dose cytotoxic therapy for bone marrow transplantation (BMT). The major pathological changes are seen in centrilobular (zone 3) hepatocytes and adjacent endothelium. Glutathione (GSH) becomes depleted following chemotherapy and experimental evidence suggests reduced levels predispose to centrilobular hepatocyte and endothelial cell injury. Animal studies have shown that glutamine infusions can maintain GSH levels and protect against free radical injury. We have prospectively studied the effect of glutamine supplementation during BMT. Thirty-four patients undergoing BMT were randomised to receive either glycl-L-glutamine (n = 18) or an isonitrogenous mixture of non-essential amino acids (n = 16). Glutamine was shown to significantly preserve protein C (days +4 and +7, P < 0.05) and albumin levels (days 0 and +4, P < 0.02). Markers of thrombin and plasmin generation (thrombin-antithrombin, prothrombin fragment F1+2 and plasmin-antiplasmin levels) were not significantly changed between the two groups. These findings suggest that glutamine preserves hepatic function but does not alter thrombin or plasmin generation during BMT. Previous studies have shown reductions in protein C, albumin, factor X and factor VII levels post BMT. Falling protein C levels have been shown to be predictive of severe VOD. These data suggest a role for glutamine in the protection of hepatic function following BMT.
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PMID:Parenteral glutamine protects hepatic function during bone marrow transplantation. 972 Jul 43

Beta (beta) and delta (delta)-hemolysin of Staphylococcus aureus strains were cultured in vitro in milk lactoserum (whey) prepared from both healthy and mastitis bovine milk. Production of beta- and delta-hemolysins were detected in 12 out of 50 strains studied. The association between N-acetyl-beta-D-glucosaminidase (NAGase) activity, plasmin activity (PL) and trypsin inhibitory capacity (TIC), known as inflammatory indicators for mastitis, and hemolytic activity were also studied. Mastitic milk decreased directly the lytic effect of both beta-and delta-hemolysins of S. aureus on hemolytical blood agar plates. S. aureus in healthy milk samples produced more beta-hemolysin (3 times) and delta-hemolysin (2 times) when compared to S. aureus supernatants in milk from infected quarters. Furthermore, beta- and delta-hemolysis correlated negatively with TIC and NAGase and PL activities. Addition of reduced glutathione (GSH) or beta-mercaptoethanol into the artificial medium enhanced hemolysins activity.
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PMID:Characterization of hemolytic activity of Staphylococcus aureus strains isolated from bovine mastitic milk. 1129 66

A condition of oxidative stress, due to perturbation of oxidant/antioxidant balance, has been suggested to play a role not only in the pathogenesis of human immunodeficiency virus (HIV) infection, but also in the promotion of a thrombophilic condition. Because various hemostatic dysfunctions usually considered as risk factors for thrombotic events were reported in HIV infection, this study was undertaken to investigate whether the oxidative phenomenon could promote a prothrombotic state in such condition. Erythrocyte glutathione peroxidase (GSH-Px), the major free-radical scavenger enzyme, and serum tumor necrosis factor-alpha (TNF-alpha) were evaluated in 33 consecutive HIV-infected out-patients and 35 matched HIV-negative healthy controls at a distance of any acute episode. Thrombin generation was explored by measuring the plasma levels of prothrombin fragment 1 + 2 (F1 + 2), whereas fibrin degradation products (D-dimer) and plasminogen activator inhibitor (PAI-1) activity were evaluated as indices of plasmin activity and fibrinolytic derangement. The anticoagulant pathway was investigated by measuring the plasma levels of antithrombin and protein C. Erythrocyte GSH-Px activity and serum TNF-alpha were significantly higher in HIV-infected patients when compared to controls. F1 + 2, D-dimer, and PAI-1 activity were increased in HIV-infected patients by comparison with controls. Normal antithrombin, but decreased protein C, was instead detected in HIV-infected patients. In the latter patients, serum TNF-alpha negatively correlated with both erythrocyte GSH-Px activity and plasma D-dimer. On the other hand, a positive correlation was shown between F1 + 2 and D-dimer and between D-dimer and GSH-Px activity. Furthermore, a trend toward increasing levels of GSH-Px with increasing PAI-1 activity was reported. These findings suggest a relationship between erythrocyte oxidative stress and the hypercoagulable condition during HIV infection.
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PMID:Increased erythrocyte glutathione peroxidase activity and serum tumor necrosis factor-alpha in HIV-infected patients: relationship to on-going prothrombotic state. 1198 8

Transforming growth factor-beta1 (TGF-beta1) promotes tissue fibrosis by upregulating genes encoding extracellular matrix proteins and by increasing the synthesis of plasminogen activator inhibitor-1 (PAI-1). TGF-beta1 induces cellular reactive oxygen species (ROS) and PAI-1 promoter region has binding sites for redox sensitive transcription factors. We, therefore, hypothesized that TGF-beta1-induced upregulation of PAI-1 is ROS-dependent. Using cultured glomerular mesangial cells, we confirmed that TGF-beta1 induces cellular ROS, upregulates PAI-1 mRNA and protein expression, and suppresses plasmin activity. We further demonstrated that H(2)O(2) stimulates PAI-1 expression and suppresses plasmin activity and that N-acetylcysteine effectively reverses TGF-beta1- and H(2)O(2)-induced changes in PAI-1 expression and plasmin activity. Basal as well as TGF-beta1- and H(2)O(2)-induced PAI-1 expression was upregulated by depletion of intracellular GSH. The present data demonstrate that TGF-beta1-induced PAI-1 in mesangial cells is ROS-dependent and imply that cellular ROS may be potential therapeutic targets in glomerular fibrosis.
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PMID:Reactive oxygen species mediate TGF-beta1-induced plasminogen activator inhibitor-1 upregulation in mesangial cells. 1367 67

Transforming growth factor (TGF)-beta plays an important role in tissue fibrogenesis. We previously demonstrated that reduced glutathione (GSH) supplementation blocked collagen accumulation induced by TGF-beta in NIH-3T3 cells. In the present study, we show that supplementation of GSH restores the collagen degradation rate in TGF-beta-treated NIH-3T3 cells. Restoration of collagen degradation by GSH is associated with a reduction of type I plasminogen activator inhibitor (PAI)-1 expression/activity as well as recovery of the activities of cell/extracellular matrix-associated tissue-type plasminogen activator and plasmin. Furthermore, we find that NIH-3T3 cells constitutively express plasminogen mRNA and possess plasmin activity. Blockade of cell surface binding of plasminogen/plasminogen activation with tranexamic acid (TXA) or inhibition of plasmin activity with aprotinin significantly reduces the basal level of collagen degradation both in the presence or absence of exogenous plasminogen. Most importantly, addition of TXA or active PAI-1 almost completely eliminates the restorative effects of GSH on collagen degradation in TGF-beta treated cells. Together, our results suggest that the major mechanism by which GSH restores collagen degradation in TGF-beta-treated cells is through blocking PAI-1 expression, leading to increased PA/plasmin activity and consequent proteolytic degradation of collagens. This study provides mechanistic evidence for GSH's putative therapeutic effect in the treatment of fibrotic disorders.
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PMID:Glutathione restores collagen degradation in TGF-beta-treated fibroblasts by blocking plasminogen activator inhibitor-1 expression and activating plasminogen. 1625 2

In this review, we hypothesized the importance of the interaction between the brain glutathione (GSH) system, the proteolytic tissue plasminogen activator (t-PA)/plasminogen/ plasmin system, regulated by plasminogen activator inhibitor (PAI-1), and neuroserpin in the pathogenesis of Alzheimer's disease. The histopathological characteristic hallmark that gives personality to the diagnosis of Alzheimer's disease is the accumulation of neurofibroid tangles located intracellularly in the brain, such as the protein tau and extracellular senile plaques made primarily of amyloidal substance. These formations of complex etiology are intimately related to GSH, brain protective antioxidants, and the proteolytic system, in which t-PA plays a key role. There is scientific evidence that suggests a relationship between aging, a number of neurodegenerative disorders, and the excessive production of reactive oxygen species and accompanying decreased brain proteolysis. The plasminogen system in the brain is an essential proteolytic mechanism that effectively degrades amyloid peptides ("beta-amyloidolysis") through action of the plasmin, and this physiologic process may be considered to be a means of prevention of neurodegenerative disorders. In parallel to the decrease in GSH levels seen in aging, there is also a decrease in plasmin brain activity and a progressive decrease of t-PA activity, caused by a decrease in the expression of the t-PA together with an increase of the PAI-1 levels, which rise to an increment in the production of amyloid peptides and a lesser clearance of them. Better knowledge of the GSH mechanism and cerebral proteolysis will allow us to hypothesize about therapeutic practices.
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PMID:Beta-amyloidolysis and glutathione in Alzheimer's disease. 2365 Apr 62

Enzymes have many important roles in biology and industry, and proteases are one of the most important classes of enzymes. Semiconductor quantum dots (QDs) are attractive materials for developing protease activity probes because of their advantageous physical and optical properties; however, interactions between a protease and a QD conjugated with its substrate can affect the turnover of that substrate. Here, we study the turnover of multivalent QD-peptide substrate conjugates as a function of multiple parameters: (i) the ligand coating on the QD, including dihydrolipoic acid (DHLA), glutathione (GSH), DHLA-poly(ethylene glycol) (DHLA-PEG), and DHLA-zwitterionic sulfobetaine (DHLA-SB); (ii) the identity of the protease, including trypsin, thrombin, and plasmin; and (iii) the number of substrate and nonsubstrate biomacromolecules conjugated per QD. We show that limiting protease adsorption on QDs is critical for optimizing the turnover of conjugated peptide substrates. Protease adsorption is inhibitory, and very strong adsorption leads to an apparent "scooting" mode of activity with limited turnover. In contrast, with weaker adsorption, enhancements in the turnover rate likely result from a "hopping" mode of activity. The putative hopping mode is thought to feature processive turnover of all substrates in multivalent conjugates with a rate-limiting step of diffusion between individual conjugates, and the magnitude of such enhancements increases with decreases in adsorption. Although it was possible to passivate DHLA- and GSH-coated QDs with high densities of conjugated biomacromolecules, the most effective strategy for reducing adsorption was the substitution of these ligands. Whereas passivation incrementally increased turnover, DHLA-PEG and DHLA-SB ligands converted the mode of turnover with plasmin from scooting to hopping and the DHLA-SB enhanced the turnover rates with thrombin and trypsin by approximately an order of magnitude relative to GSH ligands. The new insights from the broad scope of this study provide an important framework for designing optimized QD conjugates as probes and sensors for enzyme activity.
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PMID:Optimization and Changes in the Mode of Proteolytic Turnover of Quantum Dot-Peptide Substrate Conjugates through Moderation of Interfacial Adsorption. 2884 81


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