Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

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

Trypsin (Try), plasma kallikrein (KK) and plasmin activities together with coagulation factor XII (F XII, Hageman factor), high-molecular-weight kininogen (HMWK), plasma prekallikrein (PKK), alpha 2-macroglobulin (alpha 2-M), C1 inhibitor (C1Inh), and functional plasma kallikrein inhibition (KKI) values were studied in peritoneal fluid and lavage taps of 9 patients with severe acute pancreatitis treated with peritoneal lavage. Both immunochemical methods and functional techniques based on chromogenic peptide substrate assays were used. In the exudate obtained before peritoneal lavage was performed, F XII was 52%, HMWK was 30%, PKK was 40%, alpha 2-M was 29% and C1Inh was 57% of standard plasma pool values, determined by immunochemical technique. Functional plasma KKI values were zero, whereas Try activities determined by chromogenic peptide substrate technique were markedly elevated in the exudate. Using a prepacked HR 10/30 Superose Tm 12 column (Pharmacia, Uppsala, Sweden) and chromogenic peptide substrate assays, Try and KK activities were detected in the alpha 2-M containing fractions of the peritoneal exudate demonstrating KK-alpha 2-M and Try-alpha 2-M complex formation. The peritoneal lavage procedure efficiently eliminated components of the contact system and protease activities. In the first lavage tap, Try activities were markedly reduced compared to values found in the exudate and concentrations of F XII, HMWK, PKK, alpha 2-M and C1Inh were all zero. In consecutive lavage taps Try values were also zero. The study shows that the lavage procedures efficiently clears the peritoneal cavity for protease-alpha 2-M complexes generated during acute pancreatitis. Also, components of the contact system found in peritoneal exudate, and which might serve as substrates for the protease-alpha 2-M complexes, are rapidly eliminated by the procedure.
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PMID:Peritoneal lavage efficiently eliminates protease-alpha-2-macroglobulin complexes and components of the contact system from the peritoneal cavity in patients with severe acute pancreatitis. 246 82

We examined the effect of a serratial exoprotease on the pathogenesis of influenza virus infection in mice as a model of complicated respiratory infection by bacteria and virus in humans. The 56-kilodalton (56-kDa) protease from Serratia marcescens was administrated intranasally to mice at a dose of 10, 20, or 40 micrograms from day 0 to day 3 after inoculation of the influenza virus. Administration of the protease resulted in remarkable enhancement of the lethal effect of the virus and enhancement of pathological changes in the lungs. Influenza virus replication, determined by plaque-forming assay, was accelerated by the protease. Namely, we found a 100-fold increase in virus yield by day 2. The 56-kDa protease caused generation of plasmin activity in the lungs. In vitro experiments showed that plasmin greatly enhanced the yield of influenza virus, although the effect of the 56-kDa protease by itself was much lower than that of plasmin. Furthermore, the 56-kDa protease could induce plasmin production indirectly via activation of plasminogen by the Hageman factor-dependent cascade in the in vitro system. We conclude that this major serratial exoprotease has a deleterious effect on mice infected with influenza virus and that this effect seems to result from enhancement of viral growth by indirect acceleration of plasmin generation induced by the protease.
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PMID:Molecular mechanism of complex infection by bacteria and virus analyzed by a model using serratial protease and influenza virus in mice. 252 98

The nature of vascular permeability factor (VPF) activity derived from serum-free conditioned medium containing cultured human malignant glial tumors has been further investigated. A 1000-fold purification was accomplished by sequential heparin-Sepharose affinity chromatography and high-performance liquid chromatography gel filtration chromatography steps. Vascular permeability factor activity falls into a molecular weight range of 41,000 to 56,000 D. Activity is bound to hydroxylapatite, carboxymethyl-Sepharose, phenyl-Sepharose, and heparin-Sepharose, whereas little or no activity was bound to diethylaminoethyl-Sephacel. Vascular permeability factor activity is trypsin- and pepsin-sensitive but is unaffected by treatment with ribonuclease A. This suggests that VPF is a hydrophobic, positively charged (cationic) polypeptide with a potentially biologically significant affinity for heparin. As most proteins are negatively charged (anionic) and have no affinity for heparin, a significant advantage was gained by performing these purification steps. The activity of VPF is not inhibited by coinjection of conditioned medium with soybean trypsin inhibitor; or hexadimethrine (both known antagonists of tissue plasminogen activator, Hageman factor, and serum kallikrein); or aprotinin (an antagonist of both plasmin and tissue kallikrein); or phenylmethanesulfonyl fluoride (a serine esterase (elastase) inhibitor); or pepstatin-A (an acid protease inhibitor which inactivates vascular permeability-inducing leukokinins). These data, together with the fact that VPF is produced and released into serum-free media, provides substantial evidence against it being one of the more commonly known serum-derived permeability mediators. Treatment with dithiothreitol inhibited VPF activity, indicating the presence of at least one essential disulfide bond in this molecule. Inhibition by dexamethasone of VPF expression in cultured malignant glial cells appears to be selective. Dexamethasone-induced inhibition of VPF was dose-responsive and was not associated with a parallel inhibition of cellular protein synthesis as determined by tritiated leucine incorporation into trichloroacetic acid-precipitable material. Inclusion of dexamethasone in the culture medium was not associated with altered cell viability or cell number. A series of in vivo studies confirmed the inhibition of VPF activity in test animals pretreated with dexamethasone. This steroid-induced inhibition was partially reversed by treatment of test animals with actinomycin D prior to exposure to dexamethasone.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Further characterization of malignant glioma-derived vascular permeability factor. 313 21

The inhibitory effects of 6-amidino-2-naphthyl-4-guanidinobenzoate X dimethanesulfonate (FUT-175) on the human Hageman factor fragment (HFf), factor Xa, thrombin, plasma kallikrein, and plasmin were studied. FUT-175 inhibited plasma kallikrein most (IC50 = 3.0 X 10(-9) M), followed by HFf (IC50 = 3.3 X 10(-7) M). FUT-175 was found to have an anticoagulant effect in the APTT and PT assay systems of human plasma. The concentration of FUT-175 for twofold increase in the clotting time in the APTT assay system was 5 X 10(-7) M.
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PMID:Inhibitory effect of a new synthetic protease inhibitor (FUT-175) on the coagulation system. 316 8

The prognosis of septicaemia depends on the occurrence of complications such as shock and coagulation defects. The damage to haemostasis is usually explained by the action of the main coagulation and fibrinolysis enzymes, thrombin and plasmin. This paper presents data concerning the role of a third protease, granulocytic elastase. 82 patients who had been admitted to our hospital with suspected septicaemia were examined. Septicaemia was proven in 22 patients by the growth of microorganisms in blood cultures, and was clinically diagnosed in 9 patients. The plasma levels of neutrophil elastase-like protease complexed to a1antitrypsin (a1AT-ELP) were measured by zone immunoelectrophoresis assay (ZIA). The a1AT-ELP values were significantly increased in the 31 septic as compared to the 51 non-septic patients. In patients with complicated septicaemia, negative correlations of a1AT-ELP with factor XIII and the coagulation inhibitor antithrombin III were demonstrable. Among the patients with septic complications, the 3 who survived exhibited a dramatic decrease of a1AT-ELP, whereas in the other 16 patients who died the levels remained elevated. It might be of therapeutic significance that in 9 patients receiving fresh plasma and AT III-concentrate substitution for DIC the a1AT-ELP levels dropped, whereas they remained high in the other septicaemia patients. There were no correlations between a1AT-ELP and the a2antiplasmin-plasmin complexes (a2AP-P1), but strong correlations with signs of coagulation. The data suggest an interaction of coagulation and elastase release, probably involving the Hageman factor.
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PMID:Participation and interactions of neutrophil elastase in haemostatic disorders of patients with severe infections. 329 74

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

This study was performed to investigate whether the Hageman factor (HF) system might contribute to glomerular damage in vivo. HF was purified from rabbit plasma. The proteolytic activation pattern of 80,000-dalton rabbit HF was the same as that previously reported for human HF. Anti-HF IgG, raised in a goat, was monospecific as judged by immunodiffusion analysis and inhibited HF activity in rabbit plasma. A telescoped model of nephrotoxic nephritis in the rabbit was developed using guinea pig antirabbit glomerular basement membrane IgG injected into rabbits preimmunized against guinea pig IgG. In this model protein excretion was increased by days 3 to 4 in association with glomerular influx of acute inflammatory cells. By days 5 and 6 fibrin was present within glomerular capillaries, beneath endothelial cells, in Bowman's space, and in proximal tubules. By fluorescent microscopic analysis rabbit IgG and C3 had accumulated along the glomerular capillary wall; however, no HF was detectable in glomerular capillary wall over the initial 10 days of glomerular injury. Positive fluorescence for HF was seen within Bowman's space and in tubules along with albumin and plasmin- and fibrin-related antigens. Although the circulating antigenic HF concentration did not change during the glomerular injury, the rate of turnover of 125I-HF did increase. However, when this was factored for turnover of 131I-albumin in a paired study, the relative turnover of 131I-albumin was found to be faster than that of 125I-HF. Proteolysis of 125I-HF in plasma consistent with HF activation was noted in only one of these rabbits in spite of a decrease in antigenic C3 level to 54% of baseline. The 125I-HF appearing in urine of nephritic rabbits had undergone proteolysis from the native 80,000-dalton parent molecule to form fragments of 50,000 and 30,000 daltons, compatible with HF activation. Urine from nephritic rabbits also contained procoagulant activity that was HF dependent. These results are compatible with the concept that HF passively crosses the damaged glomerular filter where it may become activated in Bowman's space or in fluid draining damaged glomeruli in this model of nephrotoxic nephritis in the rabbit.
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PMID:Hageman factor in experimental nephrotoxic nephritis in the rabbit. 392 66

C1(-)-inhibitor (C1(-)-INH) proteins from normal persons and members of eight different kindred with dysfunctional C1(-)-INH proteins associated with hereditary angioneurotic edema (HANE) were compared with respect to their inhibitory activity against purified preparations of C1s-, plasma kallikrein, activated forms of Hageman factor, and plasmin. Each dysfunctional C1(-)-INH protein showed a unique spectrum of inhibitory activity against these enzymes. Although none of the dysfunctional C1(-)-INH proteins significantly impaired amidolysis by plasmin, all but one inhibited activated Hageman factor. One purified dysfunctional C1(-)-INH (Ta) inhibited purified C1s- to a normal degree. Another C1(-)-INH (Za) had almost seven times as much inhibitory activity as normal C1(-)-INH against activated Hageman factor, but had decreased activity against C1s- and no activity against plasmin. Analyses of mixtures of plasmin and C1(-)-INH proteins in SDS gel electrophoresis revealed variability in the patterns of complex formation and cleavage of dysfunctional proteins after exposure to C1s- and plasmin. Some bound to plasmin and were cleaved, even though none significantly impaired the amidolytic activity of plasmin. Two were cleaved by C1s-, whereas neither normal or other dysfunctional C1(-)-INH were cleaved. Dysfunctional C1(-)-INH proteins from patients with HANE are thus heterogeneous in their inhibitory properties and there must be different structural requirements for the inhibition of the various plasma enzymes that can be regulated by normal C1(-)-INH. The data suggest that in addition to common sites of interactions between these proteases and C1(-)-INH, there are also points of contact that are specific for each protease. Genetic mutations leading to structural changes at some of these sites may have differing effects on the interaction between individual proteases and abnormal C1(-)-INH proteins. These alterations may allow these proteins to serve as probes for structural requirements for inhibitory actions of normal C1(-)-INH.
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PMID:Variability in purified dysfunctional C1(-)-inhibitor proteins from patients with hereditary angioneurotic edema. Functional and analytical gel studies. 396

Although the biological function of histidine-rich glycoprotein (HRG) is unknown, it may serve as an antifibrinolytic agent by interfering with the binding of plasminogen to fibrin. To define the role of HRG, plasma titers were measured by single radial immunodiffusion in eleven patients with thromboembolism before and after streptokinase (SK) therapy and were found unchanged (84.7 +/- 6.2%, M +/- SEM before, and 99.5 +/- 6.3% after 12 hr of SK therapy). The HRG peaks on crossed immunoelectrophoresis before and after SK infusion were also unchanged. Alpha 2-plasmin inhibitor fell during SK infusion as measured immunologically (102.0 +/- 15.0% before and 28.0 +/- 1.6% after 12 hr of therapy) and fibrinogen-fibrin degradative products appeared (mean titer of 1:2,048 after 12 hr of therapy), indicating that the infused SK was biologically active. Plasminogen levels before therapy were normal, as measured functionally and immunologically (105.4 +/- 4.9% and 96.0 +/- 5.6%, respectively), and both decreased after 12 hr of SK therapy (15.2 +/- 5.6% and 50.8 +/- 4.3%). No changes in functional antithrombin III titer, Hageman factor antigen level, or fibrinogen concentration, as measured turbidimetrically, were observed. Thus, although these data do not allow one to make any firm conclusions regarding the physiologic role of this protein in fibrinolysis, they do not exclude its increased catabolism, compensated by increased production, in patients undergoing fibrinolytic therapy.
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PMID:Histidine-rich glycoprotein and changes in the components of the fibrinolytic system after streptokinase therapy in patients with pulmonary thromboembolism. 401 25


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