Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.73 (urokinase-type plasminogen activator)
 10,685 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It has previously been shown, that large differences exist between the effects of 6-aminohexanoic acid or alpha1-antitrypsin on fibrinolysis caused by a porcine tissue plasminogen activator or by human urokinase, while insignificant differences exist between the effects of a number of natural protease inhibitors on fibrinolysis caused by the two types of plasminogen activator. The present study shows that changes in substrate composition (pH, ionic strength fibrinogen concentration, plasminogen concentration) may influence to different degrees the fibrinolytic activities of human urokinase and the porcine tissue plasminogen activator. It is suggested, that this finding is partly related to marked differences in affinity for fibrin of the two activators.
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PMID:Differences in the reactivities of human urokinase and the porcine tissue plasminogen activator. 1 58

The assay of plasminogen activator activities on fibrin plates was re-evaluated with special reference to fibrinolysis inhibitors present in samples and in fibrin plates. The nature, action and stability of inhibiting material were studied in tissue with considerable differences in activator and inhibitor contents: human lung, liver and placenta. Extracts were tested for inhibitory capacity against purified human uterine tissue plasminogen activator, urokinase and plasmin of fibrin plates prepared from different grades of fibrinogen and fibrin. The tissue extracts inhibited fibrinolysis on fibrin plates to varying degrees, dependent on the sample medium, the type of fibrin plate and the kind of plasminogen activator. The influence of inhibitors in the sample and in the fibrin plate was partly abolished by the presence of 2 M KSCN in the sample. The procedure for preparing the samples as described by Astrup and Albrechtsen did not completely eliminate the inhibitory action against the added plasminogen activators. Comparison of urokinase inhibition with tissue activator inhibition by the tissue extracts as to the degree of denaturation in the Astrup and Albrechtsen procedure showed that they have much in common. Nevertheless, some differences were found which indicated the possible existence of separate urokinase and tissue activator inhibitors or of different inhibition mechanisms for these plasminogen activators.
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PMID:Interfering factors in the assay of plasminogen activators by the fibrin plate method. Occurrence of different inhibitors against tissue plasminogen activator and urokinase. 11 68

Two fluorogenic peptide amides have been synthesized, i.e. BOC-L-valyl-glycyl-L-arginine 2-naphthylamide (I) and L-valyl-glycyl-L-arginine 2-naphthylamide (II). The kinetic parameters of plasmin, urokinase and human uterine tissue plasminogen activator on substrates I and II have been determined. Quite unexpectedly, the tissue activator appeared to require for its activity a blocked amino terminus on the substrate. This was further corroborated with other synthetic substrates. Plasmin and urokinase did not show this requirement.
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PMID:Fluorogenic substrates for sensitive and differential estimation of urokinase and tissue plasminogen activator. 65 77

An inhibitor of urokinase present in increased concentrations in plasma during pregnancy was purified. The inhibitor was identified by its pronounced effect on urokinase-induced fibrinolysis as opposed to the absence of effect on fibrinolysis induced by a tissue plasminogen activator. The inhibitor progressively inactivated urokinase upon incubation and was found to be indistinguishable from alpha1-antitrypsin.
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PMID:Purification of a plasminogen activator inhibitor indistinguishable from alpha1-antitrypsin and an urokinase inhibitor in pregnancy plasma. 82 61

Tissue and urokinase-type plasminogen activators are serine proteases with highly restricted specificity, their best characterised role being to release the broad specificity protease plasmin from inactive plasminogen. It has frequently been suggested that these, and similar proteases, are involved in axonal growth and tissue remodelling associated with neural development. To help define what this role might be, we have studied the expression of the plasminogen activators in developing rat nervous tissue. Urokinase-type plasminogen activator mRNA is strongly expressed by many classes of neurons in peripheral and central nervous system. We have analysed its appearance in spinal cord and sensory ganglia, and found the mRNA is detectable by in situ hybridisation very early in neuronal development (by embryonic day 12.5), at a stage compatible with it playing a role in axonal or dendritic growth. Tissue plasminogen activator mRNA, on the other hand, is expressed only by cells of the floor plate in the developing nervous system, from embryonic day 10.5 and thereafter. Immunohistochemical and enzymatic analysis showed that active tissue plasminogen activator is produced by, and retained within, the floor plate. A mechanism is suggested by which high levels of tissue plasminogen activator produced by the stationary cells of the floor plate could influence the direction of growth of commissural axons as they pass through this midline structure.
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PMID:The expression of tissue and urokinase-type plasminogen activators in neural development suggests different modes of proteolytic involvement in neuronal growth. 128 56

The effect of pH and temperature on kinetic and thermodynamic parameters (i.e., k(on),k(off),Ka,delta G0, delta H0 and delta S0 values) for the binding of the Kunitz-type trypsin inhibitor DE-3 from Erythrina caffra seeds (ETI) to bovine beta-trypsin, bovine alpha-chymotrypsin, the human tissue plasminogen activator, human alpha-, beta- and gamma-thrombin, as well as the M(r) 33,000 and M(r) 54,000 species of the human urinary plasminogen activator (also named urokinase) has been investigated. At pH 8.0 and 21.0 degrees C: (i) values of the second-order rate constant (K(on)) for the proteinase:ETI complex formation vary between 8.7 x 10(5) and 1.4 x 10(7)/M/s; (ii) values of the dissociation rate constant (k(off)) for the proteinase: ETI complex destabilization range from 3.7 x 10(-5) to 1.4 x 10(-1)/s; and (iii) values of the association equilibrium constant (Ka) for the proteinase:ETI complexation change from < 1.0 x 10(4) to 3.8 x 10(11)/M. Thus, differences in k(off) values account mostly for the large changes in Ka values for ETI binding. The affinity of ETI for the serine proteinases considered can be arranged as follows: bovine beta-trypsin > human tissue plasminogen activator > bovine alpha-chymotrypsin >> human alpha-, beta- and gamma-thrombin approximately M(r) 33,000 and M(r) 54,000 species of the human urinary plasminogen activator. Moreover, the serine proteinase:ETI complex formation is an endothermic, entropy-driven, process.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Binding of the Kunitz-type trypsin inhibitor DE-3 from Erythrina caffra seeds to serine proteinases: a comparative study. 129 2

Acute myocardial infarction (AMI) is one of the most intractable diseases and is increasing rapidly in Japan and China. Two hospitals in Japan and China, the Critical Care Center of Kurume University Hospital and the Chinese Beijing 309 Hospital in China (abbreviated to Beijing 309 Hospital) were compared. The incidence, mortality and treatment of AMI were investigated in both hospitals from 1989 to 1991. The incidence of AMI for all patients admitted during the three years was 5% in Kurume University Hospital and 4.7% in Beijing 309 Hospital, which are similar rates. The average age of the patients in Beijing 309 Hospital was younger (58 +/- 13) than in Kurume University Hospital (64 +/- 11). The mortality rate in Kurume University Hospital was slightly lower than the rate in Beijing 309 Hospital (8.1% vs 8.9%). Thrombolytic therapy was actively performed in both hospitals. In Kurume University Hospital, urokinase (UK: 71.4%) or recombinant tissue plasminogen activator (rt-PA: 28.6%) was administered by intravenous (85.7%) and intracoronary percutaneous transluminal coronary recanalization (PTCR: 14.3%) injection. In Beijing 309 Hospital, UK (32.7%) or snake poison enzyme (SPE: 62.3%) was administered by intravenous (85.8%) or intra-aortic (14.2%) injection. Rt-PA was only used in Japan and SPE was only used in China, but both had very strong fibrinolytic effects and resulted in high success rates of coronary reperfusion. The incidence of direct coronary intervention with percutaneous transluminal coronary angioplasty (PTCA) and intra-aortic balloon pumping (IABP) for cardiogenic shock was much higher at Kurume University Hospital than at Beijing 309 Hospital.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Comparison of incidence, mortality and treatment of acute myocardial infarction in hospitals in Japan and China. 130 10

Procoagulant, anticoagulant, and fibrinolytic activities are associated with endothelial cells and involve the production, secretion, and receptor mediated binding of proteins involved in these processes. The procoagulant aspect of endothelial cells function involves the production and release of von Willebrand Factor(vWF), the production of tissue factor, and the presence of Factor IX/IXa receptors on the cell surface. Secretion of vWf will promote the initial steps in thrombus formation by supporting platelet-platelet interaction and platelet-subendothelial matrix adhesion. Tissue factor which is undetectable in resting cells appears after exposure to various cytokines and initiates factor VIIa activation of factors IX and X. Receptors of Factor IX/IXa are also present and mediate the assembly of the prothrombinase complex on the endothelial cell surface. The anticoagulant pathway involves the cell surface protein thrombomodulin, protein C and its cofactor protein S. Thrombomodulin binds thrombin which activates protein C which in the presence of protein S cleaves and inactivates Factors V and VIII. Inactivation of these two coagulation cofactors halts the coagulation. Finally, endothelial cells also play a pivotal role in the fibrinolytic system. Production and regulated secretion of tissue plasminogen activator creates a profibrinolytic state in the endothelial cell environment. In addition, receptors for plasminogen and urokinase are also present, constituting a cell surface mediated fibrinolytic pathway. Plasminogen activator inhibitor type I, the primary inhibitor of tPA, is also produced by endothelial cells. Thus endothelial cells can promote and inhibit fibrinolysis, depending on the prevailing environmental conditions.
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PMID:[Endothelial cells and vascular hemostasis]. 131 12

High molecular weight urokinase-type plasminogen activator (uPA) in which proteolytic activity was inactivated (diisopropyl fluorophosphate (DFP)-uPA), its amino-terminal fragment (ATF, amino acids (aa) 1-143), and fucosylated and defucosylated growth factor domains (GFD, aa 4-43) were tested for growth-promoting effects and binding in human SaOS-2 osteosarcoma cells and U-937 lymphoma cells. DFP-uPA, ATF, and both the fucosylated and defucosylated GFD were capable of competing with 125I-ATF for binding to both SaOS-2 and U-937 cells. DFP-uPA, ATF, and fucosylated GFD were also mitogenic in SaOS-2 cells and increased cell numbers. However, defucosylated GFD was nonmitogenic in SaOS-2 cells and did not stimulate cell proliferation, even though it bound to these cells in a manner equivalent to the fucosylated GFD. A nonglycosylated high molecular weight uPA expressed and purified from Escherichia coli inhibited 125I-ATF binding to SaOS-2 cells but was also nonmitogenic. No mitogenic activity was observed in U-937 cells treated with the uPA forms capable of eliciting a mitogenic response in SaOS-2 cells. Proteolytically prepared kringle domain (aa 47-135) and low molecular weight uPA (aa 144-411) did not compete for 125I-ATF binding and did not elicit any mitogenic response in either of the cell lines tested. In addition, tissue plasminogen activator (tPA), which has been shown to be homologous to uPA in its growth factor domain and is also fucosylated, did not inhibit 125I-ATF binding nor elicit any mitogenic response. These results demonstrate that the GFD, implicated in binding to the uPA receptor, is also responsible for growth factor like activity in SaOS-2 cells and that the fucosylation at Thr18 within this domain may serve as a molecular trigger in eliciting this response.
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PMID:Structural requirements for the growth factor activity of the amino-terminal domain of urokinase. 132 Nov 37

Primary fetal human adrenocortical cells of definitive zone origin were transfected by electroporation with pSV3neo, a plasmid coding for SV40 T antigen and neo, which confers resistance to the antibiotic G418. The clones obtained proliferated for 30 to 40 population doublings after isolation when grown under standard medium conditions, and then entered 'crisis'. When early-passage clones were incubated with cyclic AMP (1:1 N6-monobutyryl and 8-bromo analogues), cell rounding was observed, as in primary cultures of human adrenocortical cells. As previously shown in bovine adrenocortical cells, rounding was inhibited with a monoclonal antibody against urokinase plasminogen activator but not with a monoclonal antibody against tissue plasminogen activator. The regulation of the steroidogenic pathway in clones was investigated. The effects of cyclic AMP and activation of protein kinase C were examined in cells maintained in defined medium or in the presence of serum. 17 alpha-Hydroxylase was strongly induced by cyclic AMP, as evidenced by Northern blotting and by the conversion of progesterone or 25-hydroxy-[1,2-3H]cholesterol, this induction being blocked by low concentrations of 12-O-tetradecanoylphorbol-13-acetate (TPA). Cholesterol side-chain cleavage enzyme was strongly induced by cyclic AMP, and clones also showed low activities of 21-hydroxylase and 11 beta-hydroxylase. Under all circumstances levels of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), as assessed by Northern blotting or by conversion of 25-hydroxycholesterol, were very low. 3 beta-HSD was not induced by cyclic AMP or TPA alone, but was induced by the combination of the two agents. The regulation of 17 alpha-hydroxylase and 3 beta-HSD resembles that previously described in primary cultures of human fetal adrenocortical cells. Thus, transfection with SV40 T antigen resulted in the production of clones which preserve the unique characteristics of the human adrenal cortex.
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PMID:Expression of 17 alpha-hydroxylase and 3 beta-hydroxysteroid dehydrogenase in fetal human adrenocortical cells transfected with SV40 T antigen. 132 52


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