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)

The formation of C'1 esterase from C'1, the first component of complement, may be brought about by the action of plasmin or trypsin upon C'1s, a subcomponent of C'1. These enzymes also decrease the esterolytic activity of C'1 esterase. The formation of C'1 esterase was demonstrated by measuring the appearance of an agent or agents with esterolytic properties and the capacity to inactivate C'2 and C'4, attributes of C'1 esterase. The activity of the agent which evolved was blocked by serum inhibitor of C'1 esterase. The implications of these observations, that the formation of C'1 esterase during complement fixation is mediated by proteolytic processes, are under study. The possible inhibition of C'1q by soybean trypsin inhibitor is in agreement with this hypothesis.
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PMID:The conversion of C'IS to C'1 esterase by plasmin and trypsin. 422 64

This study demonstrates that human plasma alpha(2)-macroglobulin preparations possess an enzymic activity that degrades fibrinogen, resulting in the formation of products whose structure resembles that of circulating fibrinogen catabolites. The sequence of degradation is similar to that observed in plasmin-catalyzed digests, in that Aalpha-chain fragmentation precedes that of Bbeta-chain. The addition of plasminogen activators to plasma induced an increase in the N-alpha-tosyl-l-arginine methyl ester HCl esterase and fibrinogenolytic activity associated with alpha(2)-macroglobulin purified from this plasma, indicating that the enzymic activity of the complex was preserved and could be increased in the presence of other plasma enzyme inhibitors. Immunochemical studies demonstrated that an alpha(2)-macroglobulin-plasmin complex had formed in urokinase-treated plasma. This alpha(2)-macroglobulin preparation manifested an esterolytic profile like that of a complex prepared from plasmin and purified alpha(2)-macroglobulin. After complex formation with alpha(2)-macroglobulin in plasma, plasmin retained less than 0.1% of its fibrinogenolytic activity. That plasmin expressed its activity while bound to alpha(2)-macroglobulin was suggested by immunoprecipitation of this activity with alpha(2)-macroglobulin antibody and by the demonstration that pancreatic trypsin inhibitor did not effectively inhibit its fibrinogenolytic or esterolytic activity. These results raise the possibility that, in addition to its activity as a major plasma proteolytic enzyme inhibitor, alpha(2)-macroglobulin may modulate enzyme-substrate interactions, such as those resulting in the formation of circulating fibrinogen catabolites, by providing a mechanism for the preservation and protection of a portion of the enzymic activity in the presence of other circulating inhibitors.
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PMID:Degradation of human fibrinogen by plasms alpha2-macroglobulin-enzyme complexes. 426 29

Urokinase-activated human plasma was studied by gel electrophoresis, gel filtration, crossed immunoelectrophoresis and electroimmunoassay with specific antibodies and by assay of esterase and protease activity of isolated fractions. Urokinase induced the formation of different components with plasminogen+plasmin antigenicity. At low concentrations of urokinase, a component with a K(D) value of 0.18 by gel filtration and post beta(1) mobility by gel electrophoresis was detected. The isolated component had no enzyme or plasminogen activity. In this plasma sample fibrinogen was not degraded for 10h, but when fibrin was formed, by addition of thrombin, fibrin was quickly lysed, and simultaneously a component with a K(D) value of 0 and alpha(2) mobility appeared, which was probably plasmin in a complex with alpha(2) macroglobulin. This complex showed both esterase and protease activity. After gel filtration with lysine buffer of the clotted and lysed plasma another two components were observed with about the same K(D) value by gel filtration as plasminogen (0.35), but beta(1) and gamma mobilities by gel electrophoresis. They appeared to be modified plasminogen molecules, and possibly plasmin with gamma mobility. Similar processes occurred without fibrin at higher urokinase concentrations. Here a relatively slow degradation of fibrinogen was correlated to the appearance of the plasmin-alpha(2) macroglobulin complex. The fibrin surface appeared to catalyse the ultimate production of active plasmin with a subsequent preferential degradation of fibrin and the formation of a plasmin-alpha(2) macroglobulin complex. The gel filtration and electrophoresis of the plasma protease inhibitors, alpha(1) antitrypsin, inter-alpha-inhibitor, antithrombin III, and C(1)-esterase inhibitor indicated that any complex between plasmin and these inhibitors was completely dissociated. The beta(1) and post beta(1) components appear to lack correlates among components occurring in purified preparations of plasminogen and plasmin.
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PMID:Different molecular forms of plasminogen and plasmin produced by urokinase in human plasma and their relation to protease inhibitors and lysis of fibrinogen and fibrin. 428 70

1. Cellulose sulphate, a kinin-releasing agent, produced fibrinolytic activity in plasma when administered intravenously to the rat but not when added to fresh rat plasma in vitro. The in vivo effect was maximal within 1 min and disappeared within 10-20 minutes. It was retained in plasma taken 1 min after the injection and kept at room temperature for 30 minutes.2. A decrease of anti-fibrinolytic potency measured against urokinase-activated bovine plasmin, was shown to occur in plasma of rats given cellulose sulphate.3. Activated rat plasma lysed heat-denatured fibrin: it probably contains free plasmin as well as plasminogen activator.4. Adrenalectomized rats did not exhibit fibrinolytic activity nor statistically significant benzoyl-arginine ethyl ester-esterase activation in plasma after cellulose sulphate treatment.5. Adrenalectomized rats had significantly increased levels of plasma kininogen, but were normally sensitive to the kininogen-depleting action of cellulose sulphate.6. The increased plasma kininogen of adrenalectomized rats seems to be a consequence of the impairment of the plasminogen activating mechanism.
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PMID:Fibrinolytic activity evoked in the plasma of the normal and adrenalectomized rat by cellulose sulphate. 507 29

Hemostatic function of 129 patients with cancer of the digestive system was studied on the clinical point of view. Activator (A) and inhibitor (I) of fibrinolysis of 94 cancer tissues were determined by Malone's method. The following results were obtained: Latent DIC state was observed in the patients with advanced stage. Great majority of the patients with PT less than or equal to 85%, antithrombin III (AT III) less than or equal to 25 mg/dl, FDP greater than or equal to 5 micrograms/ml, alpha 1 antitrypsin (alpha 1 AT) greater than or equal to 340 mg/dl, plasminogen (plg) less than or equal to 10 mg/dl and alpha 2 plasmin inhibitor (alpha 2 PI) less than or equal to 80%, were eligible only for non-curative operation on the preoperative evaluations. Persistent decreases in PT, AT III, plg and alpha 2 PI mean poor prognosis, which were seen within about 6 months prior to death. In gastric cancer patients, these abnormalities showed correlations with serum choline-esterase, albumin and ferritin, and post-operative changes of these parameters suggested the recurrence. There were I activities in the cancer tissues which were scarcely detected in the normal tissues. Some differences in A/I ratios were observed on types of organs involved, histological types and differentiative degrees. There were no correlations between the hemostatic state and A/I ratios. These results indicate the clinical usefulness of the hemostatic functions of the cancer patients and the fibrinolytic properties of the cancer tissues, and also suggested that tumor bearing state, liver function and non-specific stimulating mechanisms participate in the appearance of the abnormalities.
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PMID:[Hemostatic abnormalities of the patients with cancer. Clinical significance and fibrinolytic properties of the cancer tissues]. 620 15

Plasma samples from 20 patients with acquired cold urticaria were studied. The C1-esterase inhibitor activity was found to be low, but the total C1-esterase inhibitor concentration was normal. Prekallikrein, plasmin-alpha 2-antiplasmin complex, and kallikrein-like activity were also found to be within normal limits. Cold-promoted activation of coagulation factor VII occurred in 45% of the patient plasmas and resulted in a considerable drop in C1-esterase inhibitor activity.
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PMID:On the role of the C1-esterase inhibitor in cold urticaria. 620 79

The control of coagulation and fibrinolytic events appears to be primarily due to four plasma proteinase inhibitors, antithrombin III, C-1-esterase inhibitor, alpha-2-antiplasmin, and alpha-2-macroglobulin. Results to date indicate that antithrombin III controls the activity of both thrombin and Factor Xa, C-1-esterase inhibitor controls kallikrein and probably activated Hageman Factor (Factor XIIa), and alpha-2-antiplasmin controls plasmin activity. The role of alpha-2-macroglobulin is not clear since it does not appear to be a primary inhibitor of any of the above enzymes. However, it is probable that it serves two functions, first as a "transfer" agent for the rapid removal of proteinases from the circulation which have been first bound by antithrombin III, C-1-esterase inhibitor, or alpha-2-antiplasmin. The second function is probably that of a back-up inhibitor when the levels of the three important controlling plasma proteins become low. The role of other plasma inhibitors such as alpha-1-proteinase inhibitor, alpha-1-antichymotrypsin, and the inter-alpha-trypsin inhibitor in coagulation and fibrinolysis would appear to be minor since these proteins either do not inactivate enzymes involved in these systems or do so at a rate too slow to be of biological significance.
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PMID:Control of coagulation and fibrinolysis by plasma proteinase inhibitors. 620 38

A cytosolic fraction of human small intestine was prepared. It contained esterase activity toward N-alpha-acetyl-lysine-methyl ester and amidolytic activities toward substrates S-2238, S-2288 and S-2251. In addition there was present a plasminogen activator activity which could cleave plasminogen to produce plasmin and the plasmin hydrolysed the same chromogenic substrates. Plasmin generation was also followed by a time-dependent hydrolysis of 125-I labeled plasminogen or monitored by fibrin-agar plate. The plasminogen activator was related to urinary urokinase immunologically. Anti-urokinase IgG cross-reacted with cytosolic fraction in double immunodiffusion. When the cytosolic fraction was electrophoresed in discontinuous polyacrylamide gel, two regions of hydrolytic activity toward the urokinase-specific substrate S-2444 were found. The activity of one of these regions could be completely inhibited by anti-urokinase while the other was not. The plasminogen activator was partially purified by ammonium sulfate precipitation and Concanavalin A-bound Sepharose chromatography.
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PMID:Demonstration of the presence of plasminogen activator in human small intestine. 623 45

Certain strains of Moraxella bovis produce tissue-damaging enzymes which may initiate or potentiate infectious bovine keratoconjunctivitis. Thirteen reference strains of this species were characterized physiologically and screened for production of various enzymes by some conventional biochemical tests and the API ZYM system (Analytab Products, Plainview, N.Y.). All 13 strains were hemolytic. All hydrolyzed Tween 80 and Tween 85 and displayed C4 esterase, C8 esterase-lipase, and C14 lipase activities. All produced phosphoamidase and phosphatase. All were able to hydrolyze casein and gelatin. All produced leucine and valine aminopeptidases and fibrinolysin. Twelve produced hyaluronidase or were agarolytic. Three hydrolyzed chondroitin sulfate. Nine strains autoagglutinated. Five produced catalase, and two produced cystine aminopeptidase.
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PMID:Hydrolytic enzymes of Moraxella bovis. 625 99

Culture fluids of avian sarcoma virus (ASV)-transformed but not normal chicken embryo cells frequently elicited a mitogenic response in normal avian and murine lymphocytes. We examined the possibility that plasminogen activator (PA) might be responsible for the observed mitogenic effect. PA activity, present in culture medium, was correlated positively with lymphocyte mitogenic capacity. Treatment of cells with phorbol myristate acetate, which elevates PA levels, increased mitogenesis. Similar treatment with dexamethasone, which inhibits PA biosynthesis and/or secretion, reduced lymphocyte mitogenic activity. Addition to culture fluids of either benzamidine or diisopropylfluorophosphate, both specific PA inhibitors, blocked lymphocyte proliferative responsiveness to culture fluids. In contrast, neither epsilon-amino-caproic acid nor trasylol, which inhibits plasmin esterase activity but not PA, abrogated lymphocyte responsiveness. Furthermore, purified urokinase, an enzyme of similar substrate specificity to PA, had lymphocyte stimulatory activity. These results strongly suggest that PA can function as a lymphocyte mitogen.
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PMID:Plasminogen activator is an apparent lymphocyte mitogen. 625 59


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