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)

Plasminogen was found to be present in bovine milk by crossreactivity between rabbit antiserum to plasminogen and casein prepared from milk by acid precipitation. This result was further supported by recovery of intact 125I-labeled plasminogen from rabbit milk after its intravenous injection. Freshly isolated whole bovine casein was observed to undergo slow autoproteolysis at 37 degrees C. Polyacrylamide gel electrophoresis revealed gradual disappearance of major caseins accompanied by appearance and increase in intensity of numerous electrophoretic bands. This autoproteolysis was inhibited by low concentrations of epsilon-aminocaproic acid (0.1 mM) and diisopropyl fluorophosphate (1 mM); catalytic amounts of urokinase accelerated the process. Autoproteolysis of isolated bovine beta-casein was shown by both urea and sodium dodecyl sulfate gel electrophoresis to result in formation of gamma 1- and gamma 2-caseins. Similar electrophoretic bands were formed when beta-casein was degraded by plasmin prepared from bovine blood serum. These results support the hypothesis that bovine plasmin occurs in milk and is identical to alkaline milk protease.
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PMID:Plasmin-mediated proteolysis of casein in bovine milk. 15 65

Plasminogen and plasminogen derivatives which contain lysine-binding sites were found to decrease the reaction rate between plasmin and alpha2-antiplasmin by competing with plasmin for the complementary site(s) in alpha2-antiplasmin. The dissocwation constant Kd for the interaction between intact plasminogen (Glu-plasminogen) and alpha2-antiplasmin is 4.0 microM but those for Lys-plasminogen or TLCK-plasmin are about 10-fold lower indicating a stronger interaction. The lysine-binding site(s) which is situated in triple-loops 1--3 in the plasmin A-chain is mainly responsible for the interaction with alpha2-antiplasmin. The interaction between Glu-plasminogen and alpha2-antiplasmin furthermore enhances the activation of Glu-plasminogen by urokinase to a comparable extent as 6-aminohexanoic acid, suggesting that similar conformational changes occur in the proenzyme after complex formation. Fibrinogen, fibrinogen digested with plasmin, purified fragment E and purified fragment D interfere with the reaction between plasmin and alpha2-antiplasmin by competing with alpha2-antiplasmin for the lysine-binding site(s) in the plasmin A-chain. The Kd obtained for these interactions varied between 0.2 microM and 1.4 microM; fragment E being the most effective. Thus the fibrinogen molecule contains several complementary sites to the lysine-binding sites located both in its NH2-terminal and COOH-terminal regions; these sites are to a large extent.
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PMID:On the specific interaction between the lysine-binding sites in plasmin and complementary sites in alpha2-antiplasmin and in fibrinogen. 15 66

Plasminogen-rich and plasminogen-poor radiolabeled human fibrin clots were inserted into large veins of baboons and stump-tailed monkeys. The thrombolytic effects of plasminogen activators (urokinase, streptokinase), and plasmin preparations with activator activity (streptokinase-activated human plasmin) and without activator activity (trypsin-activated porcine plasmin, Lysofibrin) were studied. Plasminogen-free and plasminogen-rich clots lysed at equal rates. Preparations with and without activator activity were equally effective as thrombolytic agents. Endogenous activation of plasminogen in the clot thus appears not to be the essential mechanism of thrombolysis. The exogenous pathway of enzyme adsorption to fibrin fibers seems to represent an important thrombolytic mechanism. Clot lysis was achieved with doses of fibrinolytic enzymes which produced little or no significant hematologic changes including hypofibrinogenemia and decreases of other blood coagulation factor levels.
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PMID:Mechanism of action of fibrinolytic enzymes in vivo. 15 24

Bovine plasma CIg, like human CIg, is a glycoprotein with a molecular weight of approximately 450,000 daltons and consists of two homologous subunits, the alpha and beta chains. These subunits are covalently linked through disulfide bridges in their carboxyl terminal domains. The carboxyl terminal regions are presumed to contain the fibrin-reactive transamidation site. The covalent incorporation of CIg into fibrin has been conclusively demonstrated by isolation of the S-carboxymethyl derivative of the CIg-fibrin-alpha chain complex and by determination of its terminal amino acid sequences. Cold-insoluble globulin has been shown to exert a stimulatory effect on the urokinase-mediated activation of bovine plasminogen to plasmin.
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PMID:Bovine plasma cold-insoluble globulin: gross structure and function. 15 11

Kabi human plasminogen and plasmin and two Behringwerke preparations of human plasminogen were examined for antigen content, purity and specific activity with the 1st International W.H.O. human plasmin reference preparation and with the plasminogen content of an 8 donor normal plasma pool. In relation to the plasminogen content of the preparation with the highest specific activity, the 8 donor plasma pool contained 0.186 mg/ml of plasminogen. This plasminogen on complete conversion to plasmin by streptokinase or urokinase corresponded to 4.35 International units/ml of plasmin as defined by the International reference preparation. Protein adsorption from highly purified plasminogens of low protein content induced variable underestimates of antigen and of biological activity. To prevent this it is recommended to issue these purified preparations in an inert carrier medium or alternatively to release these preparations with data pertaining to salt content and optical measurement prior to lyophilisation. When standards of high purity and low protein content are being examined for antigen and enzyme, it is recommended likewise that an inert protein carrier should be present in the diluent. Measurement of proactivator was considered to be unsuitable in reference to proactivator content of highly purified plasmin and plasminogen.
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PMID:The plasminogen content of commercial preparations and of normal donor plasma in relation to the plasmin content of the 1st international plasmin reference preparation. 15 12

The synthetic thrombin-inhibitor termed No. 205 (N-alpha-dansyl-L-arginine-4-ethyl-piperidine amide) found in our laboratories was studied kinetically using synthetic peptide substrates. The following results were obtained. 1. No. 205 inhibited thrombin competively with bz-Phe-Val-Arg-pNA and the Ki value obtained was extremely small, 3.7 x 10(-8) M. 2. No. 205 also inhibited trypsin competitively with bz-Phe-Val-Arg-pNA but the Ki value obtained was far larger than that for thrombin, 1.0 x 10(-5) M. 3. No. 205 inhibited F. Xa, plasmin and urokinase only to a small extent when estimated using 2 x 10(-4) M D-Val-Leu-Lys-pNA, bz-Ile-Glu-Gly-Arg-pNA and Glu-Gly-Arg-pNA, respectively. 4. No 205 differed from APPA in its specific inhibitory spectrum for thrombin as compared to trypsin, plasmin and F. Xa. The above results indicate that No. 205 is an extremely potent and highly selective reversible thrombin-inhibitor.
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PMID:Kinetic studies on the selectivity of a synthetic thrombin-inhibitor using synthetic peptide substrates. 15 13

Fibrin polymers formed from fibrinogen with thrombin in the presence of EDTA were suspended in a medium containing glucose, arabic gum and imidazole-HCl buffer and were sonicated at 20 kHz for 20 min to make a suspension containing fibrin particles of small size. The fibrin suspension was used as a substrate of plasmin for determining the enzymic activity of plasmin and plasminogen activated with urokinase. The kinetic study on the reaction of the fibrin particles with plasmin in the presence and the absence of fibrinogen revealed that Km value of fibrin for plasmin is 4.2 x 10(-7) M and the Ki value of fibrinogen is 1.2 x 10(-5) M.
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PMID:Fibrin suspension as a substrate fop plasmin: determination and kinetics. 16 68

The effect of the interaction between heparin and plasmin not only on fibrinolytic, caseinolytic and esterolytic activities but also on amidolytic activity, since plasmin has amidolytic or amidase activity, was investigated. Following were the results obtained from these investigations: 1. Heparin enhanced amidolytic activity of a fixed level of plasmin which was prepared by activating plasminogen with urokinase within the range from 2 to 64 units/ml of the final concentration of heparin. 2. Heparin also enhanced amidolytic activity of a fixed level of plasmin which was prepared by converting plasminogen with insolubilized urokinase. 3. Heparin did not enhance or inhibit fibrinolytic, caseinolytic and esterolytic activities of a fixed level of plasmin which was prepared by activating plasminogen with urokinase, in the fibrinolytic activity within the range from 0.032 to 125 units/ml, in the caseinolytic activity within the range from 0.0125 to 100 units/ml, and in the esterolytic activity within the range from 0.016 to 128 units/ml, of the final concentration of heparin respectively.
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PMID:The interaction between heparin and plasmin on amidolysis. 16 69

This review deals with aspects of fibrinolysis in which significant developments have taken place in the last few years. The structural changes of plasminogen during its activation are now identified precisely; the recent description of a thrombotic tendency in a kindred characterized by a defect of this protein emphasizes its important role in the homeostatic balance. Several activators of plasminogen are now identified; some of them, such as tissue and vascular activators, appear to have an important role in physiology and pathology. The recent characterizations of the alpha 2-antiplasmin and of antiactivators have widened our understanding of the inhibitors of fibrinolysis: a defect of the plasmin inhibitor seems to be associated with an haemorrhagic tendency, whereas high antiactivator levels were encountered in thrombotic conditions. The clinical use of fibrinolytic agents appears to be promising in conditions such as recurrent deep vein thrombosis and in the post-phlebitic syndrome. Thrombolytic therapy with urokinase or streptokinase appears to have elective indications in patients with acute deep vein thrombosis and massive life-threatening pulmonary embolism.
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PMID:Progress in fibrinolysis. 16 15

Continuous loss of bile in rats with a bile reservoir applied to the common bile duct caused an increase in specific activity of malic dehydrogenase, lactic dehydrogenase, glutamic dehydrogenase, glucose-6-phosphoric dehydrogenase, alkaline and acid phosphatase, urokinase and histidinase in the liver homogenates by the 7th day; the specific activity decreased by the 10th day. Disruption of innervation of the liver caused a sharp decrease of the ATP content and the abovementioned specifc activity in this organ. In continuous loss of bile there were revealed oscillations in the activity of the above-mentioned enzymes and sorbitol dehydrogenase in bile from the 1st to the 10th day of the experiment. Marked changes in the oscillations in the dysinnervated liver were in favour of the fact that those oscillations coursed under the control of the nervous system.
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PMID:[Enzyme activity of the bile and liver after disruption of its innervation and bile loss]. 18 5


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