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)

Human plasma was mixed with Ca++ or thrombin, and urokinase (UK) or streptokinase (SK) and a chromogenic substrate (S-2251: H-D-Val-Leu-Lys-pNA) specific to plasmin. The hydrolysis of S-2251 was higher when clot was formed by the addition of Ca++ or thrombin than in the absence of clot. The hydrolysis of S-2251 by euglobulin in the presence of UK was also higher when clot was formed, thus, inhibitors may not be related to the better activation of plasminogen, in the presence of fibrin clot. It may be suggested that plasminogen was better activated by activators (UK and SK) in the clot than in its absence.
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PMID:Influence of coagulation on the activation of plasminogen by streptokinase and urokinase. 50 5

Pregnancy Associated Plasma Protein A (PAPP-A) has been isolated from late pregnancy plasma using ammonium sulphate precipitation, ion exchange chromatography, affinity chromatography on Concanavalin-A, gel filtration and negative affinity chromatography. It was found that PAPP-A is an alpha 2-glycoprotein of 750-820 000 MW, probably a dimer with each monomer being composed of 2 polypeptide chains of 218 000 MW. The amino acid composition as well as other physicochemical characteristics are similar to human alpha 2-macroglobulin. PAPP-A exhibits in vitro an inhibition of the activity of the complement system, of the caseinolytic activity of plasmin and possibly of the urokinase activation of plasminogen. The hypothesis that PAPP-A plays a role in the regulation of fibrinolysis during pregnancy is put forward.
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PMID:Purification and characterization of pregnancy associated plasma protein A (PAPP-A). 51 34

This study was aimed to investigate the correlation between recurrent hemorrhage of ruptured intracranial aneurysm and local fibrinolytic activity of aneurysmal fibrin plug. The fibrinolytic activity of cerebrospinal fluid (CSF) was investigated in 63 patients with various neurological diseases by means of modified fibrin plate method. No plasmin was elicited in normal CSF, however, it was confirmed that CSF contained an incomplete activator which became a complete activator inthe presence of streptokinase, and plasminogen was identified in the presence of urokinase. In 26 cases of subarachnoid hemorrhage, the fibrinolytic activity of CSF occurred in the patients within two weeks following hemorrhagic ictus. In almost cases, the fibrinolytic activity of CSF was not increased in the first three weeks after the onset of hemorrhage. This result agreed with the fact that rebleeding of intracranial aneurysm tended to occur within two weeks after the hemorrhage. Therefore, intensive antifibrinolytic therapy for two weeks after onset of hemorrhage is necessary in order to prevent recurrent hemorrhage of intracranial aneurysm, and its doses should be sufficient to inhibit local fibinolysis. It has been suggested that the local fibrinolysis after subarachnoid hemorrhage would be caused by activators released from damaged surrounding brain tissues. Furthermore, it is strongly suggested from the result of our in vitro experiments that coexistence of CSF and blood play an important role to increase local fibrinolysis.
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PMID:[Fibrinolytic activity of cerebrospinal fluid in subarachnoid hemorrhage (author's transl)]. 55 78

Urokinase, streptokinase, Brinase, trypsin, and SN 687, a bacterial exoprotease, have been evaluated in an ex vivo assay system. These enzymes were injected into rabbits and the fibrinolytic activity as well as other coagulation parameters were measured by in vitro techniques. Dose-response correlations have been made using the euglobulin lysis time as a measure of fibrinolytic activity and the 50% effective dose has been determined for each enzyme. Loading doses, equal to four times the 50% effective dose were administered to monitor potential toxicity revealing that Brinase, trypsin and SN 687 were very toxic at this concentration. Having established the 50% effective dose for each enzyme, further testing was conducted where relevant fibrinolytic and coagulation parameters were measured for up to two days following a 50% effective dose bolus injection of each enzyme. Our results have demonstrated that urokinase and streptokinase are plasminogen activators specifically activating the rabbit fibrinolytic system while Brinase, trypsin and SN 687 increase the general proteolytic activity in vivo. The advantages of this ex vivo assay system for evaluating relative fibrinolytic potencies and side effects for plasminogen activators and fibrinolytic proteases have been discussed.
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PMID:A comparative ex vivo study of plasminogen activators and proteases for fibrinolytic activity and side effects in rabbits. 57 12

The term "effective activator" of plasminogen is proposed, to denote the resultant of activator-antiactivator interaction, and a method for the determination of the level of these activators is described. By adding axcess plasminogen to the euglobulin fraction of plasma the influence of the level of endogenous plasminogen and of the antiplasmin is eliminated. It is shown that the level of fibrinogen has very little bearing on the results. An effective activator unit is defined as equal to 1 CTA unit of urokinase activity on a fibrinogen-plasminogen substrate.
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PMID:A new method for the determination of plasma activators fibrinolysis. 57 25

The optimal conditions for the measurement of the fibrinolytic factors of plasma were examined using human and bovine plasminogen-rich fibrinogen or plasminogen-free fibrinogen as the substrates using the one dimensional diffusion method. The results were as follows: 1. There was no essential difference found between using human or bovine fibrinogen. 2. The levels of proactivator-plasminogen and plasminogen could be measured while using either plasminogen-rich or plasminogen-free fibrinogen. But, in using the latter, the proactivator-plasminogen level could not be measured, if a final concentration of more than 2,000 Christensen units of streptokinase were employed. 3. When using plasminogen-rich fibrinogen, anti-plasmin(s) and anti-activator(s) could be measured while using urokinase and plasmin, but not while using streptokinase. However, further study should be given to the measurement of the inhibitors, when using plasminogen-free fibrinogen.
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PMID:A method for the measurement of fibrinolytic activity based on one dimensional diffusion using small glass tubes. II. With special reference to the differences between the use of plasminogen-rich fibrinogen and that of plasminogen-free fibrinogen as the substrates. 57 26

Most of the technical problems associated with the fibrin plate method have been overcome in recent years with the exception of the long incubation period. This study was carried out to investigate plasminogen-enrichment as a means of shortening this period. Fibrin plates made up to contain 2.0 casein units of added plasminogen each, were opaque, firm, did not lyse spontaneously and yielded biometrically-valid parallel-line assays for streptokinase and urokinase after a 3 hour incubation period. Urokinase assays were more accurate than those for streptokinase probably because of the latter's shallow dose-response curve. Plasminogen-enrichment appears therefore to be a convenient way of producing a "rapid" fibrin plate requiring incubation for 3 hours compared with the usual 16 to 20 hours.
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PMID:The rapid fibrin plate - a method for plasminogen activator assay. 57 95

Cell cultures were prepared from nine human brain tumors. Fibrin plate assays showed plasminogen-dependent fibrinolytic activity in lysates and in material released by these neoplastic cells but not in those from normal adult human white matter. Antibodies against human urokinase caused catalytic inhibition of the urokinase and of the plasminogen activator from WI-38 cells, simian virus 40-transformed WI-38 cells, human prostatic cells, and human ovarian carcinoma cells. However, the anti-urokinase immunoglobulin G did not inhibit the plasminogen activator activity of any of the human brain tumor preparations. These studies indicate that the plasminogen activator produced by human brain tumor cells is antigenically different from the plasminogen activator of other human normal and neoplastic cells.
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PMID:In vitro plasminogen activator activity in human brain tumors. 62 Apr 2

Serine proteases or esterases released from cell cultures into the growth medium were converted to radioactive derivatives by active site labeling with tritiated DFP, both in the presence and absence of other competing active site reagents. The individual labeled enzymes were then identified by SDS-polyacrylamide gel electrophoresis and scintillation autoradiography. Conditioned medium from embryonal mouse fibroblasts transformed by mouse sarcoma virus contained five serine enzymes that were not present in medium from normal cells; two serine enzymes were released by both cell types, and one serine enzyme was found only in medium from normal cells. Two of the enzymes released by transformed cells were identified as plasminogen activators; these accounted for most of the serine enzyme labeling in transformed culture media and for most of the serine enzyme difference between normal and transformed cultures. The culture fluids from two cell strains of human neoplastic origin were examined by the same method. A rhabdomyosarcoma strain released eight serine enzymes (mol wt ranging from 22,500 to 102,000), four of which were plasminogen activators; seven serine enzymes (mol wt 26,000-102,000), including two plasminogen activators, were detected in medium from human melanoma cultures. In terms of electrophoretic mobility two of the plasminogen activators from rhabdomyosarcoma were identical with those from melanoma cultures, while the remaining two rhabdomyosarcoma activators coincided with activators found in commerical urokinase.
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PMID:Serine enzymes released by cultured neoplastic cells. 63 49

Plasminogen activator activity was detected in human gynecologic specimens using a synthetic fluorogenic peptide substrate assay and confirmed by an 125I-labeled fibrin plate assay. Epithelial cells in these samples contain enzymatic activity that biochemically resembles both the well-characterized plasminogen activator, urokinase, and the less-specific plasminogen activator, trypsin. Inhibition of the cervical cell activity by diisopropylfluorophosphate and p-nitrophenyl-p'-guanidinobenzoate demonstrates that, like urokinase and trypsin, this plasminogen activator is also a serine protease. Polyacrylamide gel electrophoresis of plasminogen that had been incubated with cervical cells indicated the same mechanism of plasminogen activation as exhibited by urokinase. We attempted to correlate plasminogen activator activity of each sample with cytomorphologic diagnosis. Three of the four dysplastic samples analyzed showed higher plasminogen activator activity than did the normal samples.
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PMID:Characterization of plasminogen activator in human cervical cells. 65 74


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