Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.7 (plasmin)
 9,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

alpha 2-Plasmin inhibitor (alpha 2PI) has been recently characterized as a fast-reacting inhibitor of plasmin in human plasma and appears to play an important role in the regulation of fibrinolysis in vivo. We have studied the effect of purified alpha 2PI upon various proteases participating in human blood coagulation and kinin generation. At physiological concentration (50 microgram/ml), alpha 2PI inhibited the clot-promoting and prekallikrein-activating activity of Hageman factor fragments, the amidolytic, kininogenase, and clot-promoting activities of plasma kallikrein, and the clot-promoting properties of activated plasma thromboplastin antecedent (PTA, Factor XIa) and thrombin. alpha 2PI had minimal inhibitory effect on surface-bound activated PTA and activated Stuart factor (Factor Xa). alpha 2PI did not inhibit the activity of activated Christmas factor (Factor IXa) or urinary kallikrein. Heparin (1.5-2.0 units/ml) did not enhance the inhibitory function of alpha 2PI. These results suggest that, like other plasma protease inhibitors, alpha 2PI possesses a broad in vitro spectrum of inhibitory properties.
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PMID:Inhibitory spectrum of alpha 2-plasmin inhibitor. 15 64

Blood clotting and fibrinolytic systems were studied in the plasma of a sei whale (Balaenoptera borealis). The sei whale belongs to the suborder baleen whales of the order Cetacea. Whale plasma had a greatly prolonged kaolin-activated partial thromboplastin time and was deficient in Hageman factor (factor XII), Fletcher factor (a plasma prekallikrein), and PTA (factor XI). All other clotting factor activities were present in amounts comparable to that of normal human plasma. Whale plasminogen was activated by human urokinase, but not by streptokinase. Whale plasma contained inhibitory activities against thrombin, activated Stuart factor, activated PTA, activated Fletcher factor, and plasmin.
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PMID:Studies on the blood clotting and fibrinolytic system in the plasma from a sei (baleen) whale. 96 76

An inhibitor of procoagulant and fibrinolytic enzymes was derived from cabbage seeds by a procedure using acetone precipitation, ion-exchange chromatography, and gel filtration. The cabbage seed inhibitor was a 10-Kd monomeric protein with intrachain disulfide bonds. This preparation prevented clot formation in whole blood and blocked the ability of thrombin to induce clot formation in plasma and to induce platelet aggregation. A number of proteases were inhibited, as demonstrated by using purified enzymes in amidolytic assays. Tight-binding inhibition was observed for activated Stuart factor (factor Xa) and plasmin. Inhibition of thrombin and activated Hageman factor (factor XIIa) was observed with a molar excess of inhibitor. No inhibition was detected for activated plasma thromboplastin antecedent (factor XIa), plasma kallikrein, or C1 esterase. Reaction progress curves for trypsin indicated slow, tight-binding inhibition, with an apparent inhibition constant in the nanomolar range or less. The electrophoretic mobility of trypsin was altered by the inhibitor in nondenaturing polyacrylamide gel electrophoresis (PAGE) but not in sodium dodecyl sulfate (SDS)-PAGE, indicating noncovalent bonding. Only partial reversal of trypsin inhibition could be demonstrated by washing the inhibitor from enzyme immobilized on solid beads. A dot-blot technique with cabbage seed inhibitor was capable of detecting 10 ng nitrocellulose-bound trypsin. The dot-blot technique also appeared capable of detecting plasmin. These findings demonstrated the potential utility of this inhibitor as a probe for detection of tightly bound proteases. In summary, cabbage seed extracts contain an inhibitor with activity toward a broad range of proteases important to hemostasis. To our knowledge, this agent represents the first inhibitor isolated from a plant source that inhibits thrombin.
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PMID:Cabbage seed protease inhibitor: a slow, tight-binding inhibitor of trypsin with activity toward thrombin, activated Stuart factor (factor Xa), activated Hageman factor (factor XIIa), and plasmin. 213

Studies of the clotting mechanisms in the plasma of a Burmese python (Python molurus bivittatus) confirm earlier information that both extrinsic and intrinsic pathways of thrombin formation participate in reptilian hemostasis. Plasma fibrinogen was present at a concentration comparable to that in human plasma. Other assays were hampered by the need to use nonreptilian reagents. The activated partial thromboplastin time was shorter than was that of human plasma, thus implying the presence of prothrombin in python plasma; however, this protein could be demonstrated only in trace amounts. Similarly, only small amounts of Hageman factor (factor XII) and antihemophilic factor (factor VIII) were detected, and none of plasma prekallikrein, high-molecular-weight kininogen, and Christmas factor (factor IX). The prothrombin time was slower than that of human plasma. Factor VII was not detected, but both proaccelerin (factor V) and Stuart factor (factor X) were present. Python plasma inhibited bovine thrombin and human plasmin, but it was deficient in fibrinolytic capacity.
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PMID:Notes on clotting in a Burmese python (Python molurus bivittatus). 234 66

Suspensions of peripheral blood mononuclear cells (PBMC), monocytes, T or B lymphocytes, platelets or granulocytes, and cell-depleted supernatant fluids of these suspensions inhibited activation of Hageman factor (HF, Factor XII) by ellagic acid, a property not shared by erythrocytes. PBMC also inhibited HF activation by glass or sulfatides. Contaminating platelets may have contributed to inhibition by PBMC. Elaboration of agents inhibiting HF activation required metabolically active cells. The inhibitor(s) in PBMC supernates were not identified with known agents, but had properties of a nonenzymatic protein. PBMC supernates did not contain fibrinogen, nor alter the thrombin, prothrombin, or partial thromboplastin times of normal plasma, amidolysis by activated plasma thromboplastin antecedent (Factor XIa) or activated Stuart factor (Factor Xa) or esterolysis by C1 (C1 esterase); they inhibited plasmin minimally. These experiments suggest that peripheral blood cells may impede intravascular coagulation. Whether this property helps maintain the fluidity of blood is unclear.
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PMID:Inhibition of the activation of Hageman factor (factor XII) by peripheral blood cells. 349 41

Activation of bovine plasma prekallikrein was investigated with several proteinases. Highly purified bovine plasma prekallikrein was rapidly activated to kallikrein [EC 3.4.21.8] by bovine activated Hageman factor, trypsin [EC 3.4.21.4] and Pronase P (proteinases from Streptomyces griseus) and more gradually by papain [EC 3.4.22.2] and ficin [EC 3.4.22.3]. Activation of prekallikrein was also observed with bovine plasmin [EC 3.4.21.7], but not with bovine clotting factors Xa (Stuart factor) [EC 3.4.21.6] and IXa (Christmas factor) or thrombin [EC 3.4.21.5]. Urokinase [EC 3.4.99.26], Reptilase, collagenase [EC 3.4.24.3], elastase [EC 3.4.21.11], alpha-chymotrypsin [EC 3.4.21.1], Nagarse [EC 3.4.21.14], and stem bromelain [EC 3.4.22 4] did not convert prekallikrein to kallikrein. Plasma kallikrein activated to Hageman factor released kinin rapidly from bovine high molecular weight (HMW) kininogen. However, from bovine low molecular weight (LMW) kininogen, liberation of kinin was extremely slow. The kallikrein activity was inhibited by soybean trypsin inhibitor (SBTI), Trasylol, diisopropylfluorophosphate (DFP), and N-alpha-tosyl-L-lysine chloromethylketone (TLCK), but not by egg-white trypsin inhibitor (EWTI), lima bean trypsin inhibitor (LBTI), heparin or hexadimethrine bromide (Polybrene). The kallikrein formed an enzyme-inhibitor complex with SBTI and Trasylol, but not with LBTI. Prekallikrein did not react with SBTI. Prekallikrein consists of a single polypeptide chain of molecular weight about 90,000, as estimated by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. Activation of prekallikrein by Hageman factor was found to involve cleavage of the single peptide bond on the disulfide-bridged polypeptide chain, and no change of molecular weight was observed during the activation. The peptide bond cleaved in prekallikrein by the activation was an Arg-X peptide bond on a disulfide-bridged polypeptide chain.
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PMID:Studies on prekallikrein of bovine plasma. II. Activation of prekallikrein with proteinases and properties of kallikrein activated by bovine Hageman factor. 676 24

Amyloid precursor protein forms that contain Kunitz protease inhibitor domains are released from activated platelets, T-lymphocytes, and leukocytes and inhibit trypsin, plasmin, and activated factor XI. We investigated the effects of amyloid precursor protein isoforms on activated Hageman factor (factor XII), activated factor X (Stuart factor), and thrombin. Recombinant amyloid precursor proteins with or without the Kunitz domain, 770 and 695 amino acids, respectively, were produced in insect cells by Baculovirus expression (BAC770 and BAC695). Neither BAC695 nor BAC770 inhibited human alpha-thrombin or activated factor X. The partial thromboplastin time was prolonged by both amyloid precursor proteins, only one of which, BAC770, contains the Kunitz protease inhibitor domain. Both forms of amyloid precursor proteins inhibited ellagic acid-induced activation of Hageman factor but did not inhibit activated Hageman factor. Bismuth subgallate, which is an insoluble analog of ellagic acid, lost its ability to activate Hageman factor on being exposed to BAC770. Inhibition of ellagic acid-induced activation of Hageman factor by both forms of amyloid precursor protein was enhanced by heparin. These findings suggested that the heparin-binding domain of amyloid precursor proteins is not in the Kunitz domain. This heparin-binding domain may block the activation of Hageman factor by negatively charged agents. Thus, amyloid precursor proteins may be involved in the control of hemostasis, properties not all dependent on the Kunitz domain.
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PMID:Inhibitory action of amyloid precursor protein against human Hageman factor (factor XII). 784 73

Thrombokinase of the blood, while resembling enterokinase in its role of activator, is more closely analogous to trypsin in its intrinsic origin. It probably arises from a plasma precursor; but it is different from plasmin (fibrinolysin). Like trypsin, thrombokinase can activate prothrombin without the aid of other factors; however, it is potentiated by platelets plus calcium. Unlike certain tissue "thromboplastins," it does not sediment appreciably in 2 hours at 85,000 g. Like trypsin, it hydrolyzes p-toluenesulfonylarginine methyl ester (TAMe). Chromatography on DEAE-cellulose separated thrombin from thrombokinase. The TAMe esterase associated with the thrombokinase fractions was largely suppressed by soybean trypsin inhibitor, while that associated with the thrombin fractions was not. Highly purified thrombokinase was used as starting material; and thrombokinase was eluted in the last major protein band. Under these conditions stepwise elution was as effective as gradient in leading to further purification. The product of 199 liters of bovine plasma was chromatographed in 1 day; and the specific activity was comparable to that attained previously by repeated electrophoretic fractionations. The assembled data suggest that the thrombokinase protein may be approaching homogeneity.
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PMID:Thrombokinase of the blood as trypsin-like enzyme. 1403 95