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

The effect of surface-bound immune complexes on the secretion of neutral proteases by human peripheral monocytes was examined. Monocytes cultured on 125I-fibrin secreted plasminogen activator in a continuous fashion. Monocytes incubated on 125I-fibrin with surface-bound immune complexes displayed a burst of plasminogen-independent fibrinolytic activity, whereas no release of plasminogen activator was observed through 21 h. The plasminogen-independent fibrinolytic enzymes were derived from monocytes and not from lymphocytes or contaminating polymorphonuclear neutrophils. The effects of various protease inhibitors on the secretion of plasminogen-dependent and independent enzymes were determined. Chymostatin selectively inhibited the monocyte-derived plasminogen activators. Similar effects of chymostatin were observed on human urokinase in the absence of cells. The predominant protease producing plasminogen-independent fibrinolysis exhibited responses to inhibitors characteristic of leukocyte elastase. When monocytes were cultured on 125I-fibrin with adherent immune complexes approximately equal to 40% of the solubilized radioactivity represented deiodination and not proteolysis. It was concluded that culture of human monocytes on surface-bound immune complexes stimulates the secretion of plasminogen-independent fibrinolytic proteases, primarily elastase, and of deiodinating enzymes. Under these conditions, plasminogen activator secretion is inhibited. Neutral proteases secreted from newly recruited monocytes may contribute to tissue injury in human diseases characterized by the presence of adherent immune complexes.
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PMID:Neutral protease secretion by human monocytes. Effect of surface-bound immune complexes. 42 65

We have synthesized four guanidinophenyl-substituted protio enol and iodo enol lactones (3-(4-guanidinophenyl)-6-methylidenetetrahydro-2-pyranone (1), 3-(4-guanidinophenyl)-6-(E)-(iodomethylidene)tetrahydro-2-pyran one (2), 4-(4-guanidinophenyl)-6-methylidenetetrahydro-2-pyranone+ ++ (3), and 4-(4-guanidinophenyl)-6-(E)-(iodomethylidene)tetrahydro-2-pyran one (4)) and tested them for inhibitory activity against some trypsin-like enzymes, namely trypsin, urokinase, tissue plasminogen activator (t-PA), plasmin, and thrombin, as well as alpha-chymotrypsin and human neutrophil elastase (HNE). The beta-aryl-substituted protio lactone 3 was a potent alternate substrate inhibitor of trypsin and urokinase. The alpha-aryl-substituted iodo lactone 2 was a permanent inactivator of urokinase, plasmin, t-PA, thrombin, and alpha-chymotrypsin, exhibiting a relatively high specificity for the former two enzymes. In general, these compounds showed a preference for inactivating trypsin-like enzymes over alpha-chymotrypsin and HNE. Also, within the class of trypsin-like enzymes, there was generally good selectivity of inhibition.
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PMID:Guanidinophenyl-substituted enol lactones as selective, mechanism-based inhibitors of trypsin-like serine proteases. 143 18

Previously, we have reported that some guanidino-substituted alpha- and beta-aryl enol lactones I and II behaved as selective, mechanism-based inhibitors of some trypsin-like proteases (Rai, R.; Katzenellenbogen, J.A. J. Med. Chem., submitted). In this study, we describe the synthesis and kinetic evaluation of some related, guanidino-substituted enol lactones having greater conformational mobility and affording additional hydrogen-bonding sites at the active site. The alpha-aryl-substituted lactones 1 and 2, which have greater conformational mobility in the guanidinoaryl linkage than I, selectively inhibited the trypsin-like enzymes, and they were relatively poor inactivators of alpha-chymotrypsin and human neutrophil elastase (HNE). The iodo enol lactone 2 permanently inactivated trypsin, urokinase, tissue plasminogen activator, and plasmin, showing exceptionally high specificity in its interaction with trypsin and urokinase. The selectivity pattern exhibited by the closely related, conformationally less mobile alpha-aryl-substituted iodo lactone Ib, which was previously shown to be a selective suicide substrate of urokinase and plasmin, provides an interesting comparison. The alpha-benzamido-substituted lactones 3 and 4, which afford an additional site for active-site hydrogen bonding, were found to be very potent alternate substrate inhibitors of trypsin and urokinase. In addition, the iodo lactone 4 permanently inactivated alpha-chymotrypsin. The importance of secondary interactions in increasing the specificities in the case of alpha-chymotrypsin is discussed.
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PMID:Effect of conformational mobility and hydrogen-bonding interactions on the selectivity of some guanidinoaryl-substituted mechanism-based inhibitors of trypsin-like serine proteases. 144 34

We have examined the prognostic value of the levels in the blood of granulocyte elastase-alpha 1-proteinase inhibitor (E-alpha 1-PI) complex, tumor necrosis factor-alpha (TNF-alpha) and urokinase-type plasminogen activator (u-PA) in 35 patients with severe infection upon admission to an Intensive Care Unit. Fourteen patients died. No differences for E-alpha 1-PI complex were found between survivors and nonsurvivors, but in all patients the levels on admission were eight-fold higher than the reference value. TNF-alpha levels, measured by immunoassay, on admission were four times higher in the nonsurvivors than in the survivors (p = 0.0003) and correlated with the severity of the disease (APACHE II score, r = 0.43, p less than 0.05). TNF-alpha was not detectable by bioassay. Total u-PA antigen (u-PA Ag), plasmin-activatable single-chain u-PA (scu-PA) and inactive, nonactivatable u-PA (u-PA#) were on admission all two-fold higher in the nonsurvivors (p = 0.0006, 0.003 and 0.0003, respectively), while normal in the survivors. In both, survivors and nonsurvivors, the ratio between scu-PA and u-PA Ag was significantly decreased (p less than 0.001, compared to a reference group of healthy volunteers), indicative for enhanced conversion of scu-PA to active two-chain u-PA (tcu-PA) and inactive u-PA# during severe infectious disease. tcu-PA was detected in nine of the 35 patients, while virtually undetectable in controls. scu-PA correlated with the Child-Pugh score on admission (r = 0.42, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Granulocyte elastase, tumor necrosis factor-alpha and urokinase levels as prognostic markers in severe infection. 151 67

The role of proteolytic enzymes in the hCG-induced increase in testicular vasopermeability and neutrophil extravasation was studied using protease inhibitors. An intra-testicular injection of hCG together with incubation medium conditioned by polymorphonuclear leucocytes (PMNs) caused a significant increase in vasopermeability and a coincident extravasation of PMN's from the postcapillary venules in the rat testis. When p-aminobenzamidine, a serine protease inhibitor which inhibits urokinase-type plasminogen activator, was administered together with hCG in the incubation medium, both the permeability increase and PMN extravasation were prevented. Aprotinin, another serine protease inhibitor, and Eglin C, a specific neutrophil elastase and cathepsin G inhibitor were, however, without effect. None of these inhibitors caused any non-specific vascular effects in the testis at the concentrations used. These results support the concept that the hCG-induced increase in vasopermeability in the rat testis is related to extravasation of PMNs and suggest that urokinase-type plasminogen activator is involved in migration of these cells through the postcapillary venular walls.
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PMID:Plasminogen activator is involved in the hCG-induced neutrophil extravasation and vasopermeability increase in the rat testis. 169 41

When human granulocytes were stimulated with the chemotactic peptide FNLPNTL (N-formyl-norleucyl-leucyl-phenylalanyl-norleucyl-tyrosinyl- lysin; in the presence of cytochalasin B), proteolytic enzymes were released which prevented activation of tumor-cell derived pro-uPA by plasmin. Elastase was identified by use of eglin C (elastase inhibitor) and an inhibitory monoclonal antibody to elastase as the functional proteolytic enzyme in these granulocyte supernatants. Purified human granulocyte elastase cleaves pro-uPA at amino acid position lle159-lle160 thus generating an enzymatically inactive two-chain form of uPA, as judged by N-terminal amino acid sequence analysis. An additional minor elastase-mediated cleavage site was detected at position Thr165-Thr166. This form of uPA was indistinguishable by SDS-PAGE from plasmin-generated enzymatically active HMW-uPA. Action of plasmin on the proenzyme form of uPA (pro-uPA) generates an enzymatically active uPA-molecule (high molecular weight form; HMW-uPA) which is cleaved at amino acid position Lys158-lle159 (Mr = 33,000 (B-chain) and 22,000 (A-chain). Thus elastase cannot substitute for plasmin in the proteolytic activation of pro-uPA to enzymatically active HMW-uPA. Enzymatically active HMW-uPA, however, was not affected by elastase. Elastase-containing granulocytes were identified by immunohistochemical staining of elastase in breast cancer tissue. Granulocytes were located close to the tumor cells and also in the tumor stroma surrounding the tumor nests. These tumor cells contain pro-uPA. Evidently, the conversion of tumor cell pro-uPA into enzymatically active HMW-uPA is controlled by elastase released from granulocytes into the tumor tissue.
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PMID:Human tumor cell urokinase-type plasminogen activator (uPA): degradation of the proenzyme form (pro-uPA) by granulocyte elastase prevents subsequent activation by plasmin. 183 19

Pro-Val pseudo dipeptides incorporating protio and halo enol lactones were tested for inhibitory activity against the serine proteases human leukocyte elastase (HLE), porcine pancreatic elastase, alpha-chymotrypsin, trypsin, thrombin, and urokinase. The protio enol lactones 1a-c were found to be HLE substrates but were poor alternate substrate inhibitors. The bromo enol lactone trans isomer 2a was found to be a very effective inhibitor of HLE and chymotrypsin, as shown by the binding constants (KI), acylation rates (ka), inactivation rates, and partition ratios determined for each enzyme. This inhibitor shows better specificity toward its target enzyme HLE than monosubstituted halo enol lactones; we attribute this to a pseudo dipeptide acyl enzyme whose structure is similar to that adopted by good peptide substrates of HLE. Inactivation of chymotrypsin by the bromo enol lactone 2a is permanent, but inactivation of HLE is partially recoverable upon treatment with the nucleophile hydrazine, indicating that lactone 2a produces two species of inactivated HLE. The more stable of these species could be the result of alkylation of His-57 by the electrophilic bromomethyl ketone revealed in the acyl enzyme, and the less stable, hydrazine-reactivatable species could be the result of alkylation of Asp-102 or the hydrolysis of the bromomethyl ketone group in the initially formed acyl enzyme to form a new, more stable acyl enzyme.
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PMID:Proline-valine pseudo peptide enol lactones. Effective and selective inhibitors of chymotrypsin and human leukocyte elastase. 198 87

Senile plaques, often surrounded by abnormally grown neurites, are characteristic of Alzheimer's diseased brain. The core of the plaque is mainly composed of amyloid beta protein (beta-AP), two of whose three precursors (APP) have serine proteinase inhibitor regions (APPI). APPI derivatives containing 60, 72 or 88 amino-acid fragments (APPI-60, APPI-72 and APPI-88, respectively) of the longest APP were produced in COS-1 cell culture medium, with the APPI cDNA ligated to the signal sequence of tissue plasminogen activator. The secreted APPIs were purified by sequential acetone precipitation followed by affinity chromatography using immobilized trypsin. These three APPIs and O-glycosylation-site-mutated APPI showed similar inhibitory activity against trypsin, chymotrypsin and plasmin. The purified APPI-72 was found to inhibit trypsin (Ki = 1.1 x 10(-10) M) and chymotrypsin (Ki = 5.8 x 10(-9) M) most strongly, and to inhibit leukocyte elastase (Ki = 7.9 x 10(-7) M) and several blood coagulation proteinases (Ki = 0.46-12 x 10(-7) M), but not urokinase or thrombin. The observed inhibition pattern was quite different from that of protease nexin I, one of serine proteinase inhibitors possessing neurite outgrowth activity. This suggests that the physiological roles of APPI are different from those of protease nexin I, and that APPI could not cause aberrant growth of neurite into the plaque. The presence of APPI having strong inhibitory activity in the brain might lead to the formation of amyloid deposits by preventing complete degradation of APPs.
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PMID:Enzyme specificity of proteinase inhibitor region in amyloid precursor protein of Alzheimer's disease: different properties compared with protease nexin I. 218 Apr 85

The [Arg15,Glu52]aprotinin gene has been constructed from a synthetic [Glu52]-aprotinin gene via an exchange of the appropriate DNA cassette. The gene has been fused to the N-terminal part of the bacteriophage MS-2 polymerase and expressed in a temperature inducible E. coli expression system. The produced fusion protein is deposited as inclusion bodies. Pure and functionally active [Arg15,Glu52]aprotinin has been obtained after cleavage of the purified fusion protein and renaturation of the aprotinin homologue. Recombinant [Arg15,Glu52]aprotinin shows good inhibition of human anionic and cationic trypsin (Ki less than or equal to 10(-11)M) and of human plasma kallikrein (Ki = 3.2 x 10(-10)M). The inhibition constants for human plasmin are Ki = 1.3 x 10(-10)M and for human urinary kallikrein Ki = 10(-11)M. No inhibition was found with the human proteinases thrombin, coagulation factor Xa, urokinase, tissue plasminogen activator, cathepsin G, leukocyte elastase and pancreatic elastase.
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PMID:Expression, isolation and characterization of recombinant [Arg15,Glu52]aprotinin. 246 33

In reaction mixtures containing Glu-plasminogen, alpha 2-antiplasmin, and tissue plasminogen activator or urokinase, either pancreatic or leukocyte elastase enhances the rate of plasminogen activation by 2 or more orders of magnitude. This effect is the consequence of several reactions. (a) In concentrations on the order of 100 nM, elastase degrades plasminogen within 10 min to yield des-kringle1-4-plasminogen (mini-plasminogen), which is 10-fold more efficient than Glu-plasminogen as a substrate for plasminogen activators. Des-kringle1-4-plasminogen is insensitive to cofactor activities of fibrin(ogen) fragments or an endothelial cell cofactor. (b) Des-kringle1-4-plasmin is one-tenth as sensitive as plasmin to inhibition by alpha 2-antiplasmin: k" = 10(6) M-1 s-1 versus 10(7) M-1 s-1. (c) alpha 2-Antiplasmin is disabled efficiently by elastase, with a k" of 20,000 M-1 s-1. The elastase-dependent reactions are not influenced by 6-aminohexanoate. In diluted (10-fold) blood plasma, the capacity of endogenous inhibitors to block plasmin expression is suppressed by 30 microM elastase. It is proposed that elastases provide an alternative pathway for Glu-plasminogen activation and a mechanism for controlling initiation of fibrinolysis by urokinase-type plasminogen activators.
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PMID:An elastase-dependent pathway of plasminogen activation. 250 79


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