Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q9UIJ5 (Rec)
 58,342 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanism of the activation of plasminogen by recombinant pro-urokinase (Rec-pro-UK), obtained by expression of the human pro-urokinase gene in Escherichia coli, was investigated in purified systems. In mixtures of Rec-pro-UK and plasminogen, both active urokinase and plasmin are quickly generated. Addition of plasmin inhibitors (aprotinin or alpha 2-antiplasmin) abolishes the conversion of Rec-pro-UK to urokinase but not the activation of plasminogen to plasmin, suggesting that Rec-pro-UK activates plasminogen directly. Human plasma competitively inhibits the activation of plasminogen by pro-urokinase with a Ki of 0.2% (v/v). This explains the relative stability of Rec-pro-UK in plasma and the lack of activation of the plasma fibrinolytic system in the absence of fibrin. The competitive inhibition by plasma is abolished by the addition of CNBr-digested fibrinogen although Rec-pro-UK has no specific affinity for fibrin. These findings suggest that the fibrin specificity of the activation of plasminogen by pro-urokinase is due to neutralization by fibrin of the competitive inhibition exerted by plasma and not to fibrin-enhanced activation of plasminogen.
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PMID:Activation of plasminogen by pro-urokinase. I. Mechanism. 293 28

The fibrinolytic and fibrinogenolytic properties of recombinant pro-urokinase (Rec-pro-UK) and recombinant urokinase (Rec-UK) were compared with those of natural urokinase (Nat-UK) and of tissue-type plasminogen activator (t-PA) in an in vitro system consisting of 125I-labeled autologous plasma clots immersed in plasma of humans, five primate species, dogs, rabbits and pigs. With each of the four plasminogen activators, a dose-dependent clot lysis was observed, the degree of which differed, however, very markedly from one species to the other. At a concentration of 100 IU/ml of urokinase extensive plasma clot lysis was obtained in plasma of man, Macaca mulatta, Macaca fascicularis and Macaca radiata, while the plasma clots of Papio cynocephalus, Papio anubis and rabbit, dog and pig were much more resistant to lysis. No significant differences in the extent of lysis were observed between Rec-pro-UK and Rec-UK nor between Rec-UK and Nat-UK. Comparable degrees of lysis were obtained with t-PA at 3- to 5-fold lower concentrations. Lysis with Rec-UK or Nat-UK was always associated with extensive activation of the fibrinolytic system in plasma, evidenced by fibrinogen breakdown and plasminogen activation and alpha 2-antiplasmin consumption. With t-PA, extensive clot lysis was obtained in the absence of fibrinolytic activation in the plasma. With Rec-pro-UK the response was intermediate; at high concentrations (200 IU/ml) extensive lysis in the reactive species was associated with fibrinogen consumption, while at intermediate concentrations (50-100 IU/ml) significant clot lysis was obtained in the reactive species in the absence of marked activation of the fibrinolytic system in the plasma.
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PMID:Biological and thrombolytic properties of proenzyme and active forms of human urokinase--IV. Variability in fibrinolytic response of plasma of several mammalian species. 649 61

The thrombolytic properties of recombinant pro-urokinase (Rec-pro-UK), recombinant active urokinase (Rec-UK) and natural urinary urokinase (Nat-UK) were compared with those of tissue-type plasminogen activator (t-PA) in rabbits with a radiolabeled thrombus in the jugular vein. The thrombolytic agents were infused intravenously over a time period of 4 hr and the extent of thrombolysis measured two hours later. In control animals the extent of thrombolysis was 11 +/- 2% (n = 8) after 6 hr. Nat-UK and Rec-UK had very similar thrombolytic properties. Significant thrombolysis was only obtained with infusion of 240,000 IU per kg (41 +/- 2%, n = 4 for Nat-UK and 37 +/- 4%, n = 4 for Rec-UK) and this was associated with a marked systemic activation of the fibrinolytic system, as evidenced by consumption of plasminogen and alpha 2-antiplasmin and fibrinogen breakdown. Infusion of Rec-pro-UK induced thrombolysis at a dose of 60,000 IU per kg (44 +/- 8%, n = 3) but without associated systemic activation of the fibrinolytic system. In this respect the properties of Rec-pro-UK were similar to those of t-PA, which, however, had a 2- to 4-fold higher specific thrombolytic activity (30,000 IU/kg yielding 48 +/- 1% lysis, n = 4). It is concluded that Rec-UK has very similar thrombolytic properties as Nat-UK and that Rec-pro-UK has a better thrombus-selectivity and less systemic side effects than the active enzymes.
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PMID:Biological and thrombolytic properties of proenzyme and active forms of human urokinase--III. Thrombolytic properties of natural and recombinant urokinase in rabbits with experimental jugular vein thrombosis. 654 17

Urokinase-type plasminogen activator (uPA) binds with high affinity to a specific cell surface glycosyl phosphatidyl-inositol (GPI)-anchored receptor, the urokinase receptor (uPAR). Pro-uPA, the enzymatically inactive single-chain form of uPA after having been activated by certain proteases, converts plasminogen into plasmin. This activation of pro-uPA to enzymatically active uPA can be prevented by the action of thrombin on pro-uPA. This inactivation process is accelerated in the presence of thrombomodulin (TM). The present study investigated whether pro-uPA bound to uPAR is still susceptible to inactivation by thrombin in the presence or absence of TM. A truncated soluble form of the uPAR lacking the GPI-anchor was cloned and expressed in CHO-cells (rec-uPAR277). Rec-uPAR277 efficiently inhibited the thrombin-mediated inactivation of pro-uPA up to 90% in a concentration dependent manner. The protective effect of rec-uPAR277 was far less pronounced when thrombin was complexed with TM. Enzyme kinetic experiments with varying concentrations of pro-uPA showed that in the presence of TM the catalytic efficiency (kcat/Km) of thrombin-mediated inactivation raised from 0.010 microM-1 s-1 to 0.50 microM-1 s-1 corresponding to a fifty-fold increase. In the presence of rec-uPAR277, however, the catalytic efficiency dropped by 4.1-fold (0.5 microM-1 s-1 to 0.122 microM-1 s-1). The inactivation kinetics of pro-uPA by thrombin (no TM added) in the presence of an excess of rec-uPAR277 could not be determined since virtually no inactivation occurred. Our data suggest that pro-uPA once bound to uPAR, is significantly protected from inactivation by thrombin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Inactivation of receptor-bound pro-urokinase-type plasminogen activator (pro-uPA) by thrombin and thrombin/thrombomodulin complex. 784 Sep 2

An experimental disseminated intravascular coagulation (DIC) was induced in female CD rats by the intravenous administration of living bacteria (9.5 x 10(7) cfu Klebsiella pneumoniae), sublethal (5 mg/kg) or lethal (50 mg/kg) lipopolysaccharide (LPS), or tissue factor (1.5 micrograms/kg i.v. bolus or 0.4 micrograms/kg x hr i.v. infusion). We used a new fibrin monomer (FM) assay to follow the course of DIC. FM were detected by their ability to stimulate the tissue-type (t-PA) plasminogen activator dependent conversion of plasminogen to plasmin by a chromogenic assay. Miniplasminogen was used instead of plasminogen to avoid interference of the assay by alpha 2-antiplasmin. As a marker of DIC, elevated levels of FM were observed with all DIC-inducing agents (plasma levels were up to 90 micrograms/ml). The kinetics of FM formation were similar to the course of thrombin-antithrombin III (TAT) levels (maximal plasma levels 70 ng/ml); however, in the bacterial infection group, both parameters rose after a lag phase of about 1 hr. A 4 hr infusion of the highly specific thrombin inhibitor recombinant (rec.) hirudin (0.125 mg/kg x hr) resulted in a decrease of FM levels from 89.2 +/- 14.4 micrograms/ml in the LPS group (n = 10) to 27.4 +/- 11.2 micrograms/ml in the rec. hirudin group (n = 10; P < 0.001). The respective values for TAT levels were 73.1 +/- 19.7 micrograms/ml in the LPS group and 52.7 +/- 15.7 ng/ml in the rec. hirudin group (P < 0.001). Other coagulation parameters, such as platelets, fibrinogen, and fibrin(ogen) degradation products, were ameliorated accordingly.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Formation of fibrin monomers in experimental disseminated intravascular coagulation and its inhibition by recombinant hirudin. 805 64

Urokinase-type plasminogen activator (uPA) activation of plasminogen is an important mediator of cell migration in many cell types. In the developing avian heart, uPA has been implicated as a mediator of atrioventricular (AV) cushion cell migration; however, the role of the plasminogen/plasmin system has not been examined. The purpose of this study was to test the hypothesis that uPA conversion of plasminogen to plasmin mediates AV cushion cell migration in vitro. Stage 17/18 chicken atrioventricular tissue lysates converted plasminogen into plasmin through uPA activity but no tissue-type plasminogen activator activity was detected. Zymograms on living cultured AV explants also activated plasminogen producing plasmin that degraded extracellular protein. The migratory capacity of cushion cells was assessed in the presence or absence of various test reagents known to alter the plasminogen/plasmin system. Addition of either human or chicken plasminogen or aprotinin (an inhibitor of plasmin) had no effect on cell migration. However, an anti-catalytic uPA antibody that blocked AV uPA activity, significantly decreased cell migration at all concentrations tested. These results showed that uPA mediated a portion of cushion cell migration in vitro. Although AV segments activated plasminogen and degraded extracellular proteins, uPA's functional role in cushion cell migration did not involve the plasminogen/plasmin system.
Anat Rec 1999 11 01
PMID:Urokinase regulates embryonic cardiac cushion cell migration without converting plasminogen. 1052 85

Lancefield group G Streptococcus canis is a component of the normal urogenital and pharyngeal flora of the cat. It is also frequently implicated in epizootics of severe disease in closed cat colonies and animal shelters. Given the importance of S canis as a feline pathogen and relative lack of published information on characteristics potentially associated with virulence, the authors have compared isolates from healthy and diseased cats in New York and California using fermentation profiles (biotype) and ScM sequences. With few exceptions, isolates associated with disease were biotype 1. Four alleles of scm were identified of which type 1 dominated in diseased cats. Type 4 allelic variants were found only in healthy cats and all but one were biotype 2. Type 2 and 3 alleles showed extensive N-terminal variation suggesting a plasminogen-binding site as found on the type 1 allele was absent. Cat antisera to ScM were opsonobactericidal, and these potentially protective antibodies increased during convalescence.
Vet Rec 2017 Apr 08
PMID:Biotypes and ScM types of isolates of Streptococcus canis from diseased and healthy cats. 2807 57