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)

Human plasmin activity is inhibited by various penicillins in a dose-dependent manner. Ampicillin and cloxacillin produce a 50% inhibition of the globinolytic activity of plasmin at 4.5 and 5.3 mM respectively. A lower inhibitory capacity is displayed by carbenicillin. Assay of plasmin by its amidolytic activity on D-valyl-L-leucyl-L-lysine p-nitroanilide dihydrochloride showed that ampicillin at a concentration producing half-maximal inhibition converted the hyperbolic activity-substrate concentration curve into a sigmoidal curve. A similar conversion occurred in the presence of ampicillin when plasmin was assayed with an alternative chromogenic substrate, L-pyroglutamyl-glycyl-L-arginine p-nitroanilide hydrochloride 6-Aminohexanoic acid at 7.5 microM abolished the inhibition of plasmin induced by ampicillin. The present observations suggest that ampicillin interacts with plasmin at a regulatory site different from the active site of the enzyme. The effect of 6-aminohexanoic acid indicates that the lysine-binding site may be part of a regulatory site. It is possible that modulation of plasmin activity by ligands plays a role in the control of fibrinolysis.
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PMID:Effects of penicillins and 6-aminohexanoic acid on the kinetics of human plasmin. 252 94

Plasmin is a labile enzyme destroyed by a process termed autodigestion. Studied by a kinetic assay on the substrate Tos-Gly-Pro-Lys-pNA this process is shown to follow a bimolecular mode of reaction, which is retarded by plasmin degradation products. Plasmin is protected by fibrinogen, by epsilon-aminocaproic acid (6-aminohexanoic acid), by increasing ionic strength, and by glycerol. CNBr fragments of fibrinogen did not protect. Lack of substrate protection of plasmin may give rise to errors in a two-stage plasminogen activator assay, while the presence of substrate in a one-stage method prevents degradation of the generated plasmin.
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PMID:The autodigestion of human plasmin follows a bimolecular mode of reaction subject to product inhibition. 293 86

One of thirty murine monoclonal antibodies, raised by immunization with human plasmin-alpha 2-antiplasmin complex, was found to be directed against the high-affinity lysine-binding site in plasminogen. Indeed, this antibody (MA-HAL) reacted with plasminogen and with a fragment of plasminogen composed of the first three triple-loop structures (LBS I) and was displaced by 6-aminohexanoic acid (50% displacement at 25 microM). In competitive radioimmunoassays the binding of radiolabeled plasminogen to MA-HAL was reduced to 50% with 2.3 microM alpha 2-antiplasmin or 1.3 microM histidine-rich glycoprotein, which corresponds to the known dissociation constants between these ligands and the high-affinity lysine-binding site of plasminogen. MA-HAL did not influence the activation of plasminogen by tissue-type plasminogen activator in the absence of CNBr-digested fibrinogen, but abolished the effect of CNBr-digested fibrinogen on the Michaelis constant of the reaction. MA-HAL reduced the reaction rate between plasmin and alpha 2-antiplasmin by a factor 20 and abolished the binding of plasminogen to fibrin. These results indicate that MA-HAL specifically binds to and masks the high-affinity lysine-binding site of plasminogen. It therefore is a useful tool for the investigation of the role of this structure in the regulation of fibrinolysis, both at the level of fibrin-stimulated activation of plasminogen and of the inhibition of generated plasmin.
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PMID:A monoclonal antibody directed against the high-affinity lysine-binding site (LBS) of human plasminogen. Role of LBS in the regulation of fibrinolysis. 294 88

An antibody population that reacted with the high-affinity lysine binding site of human plasminogen was elicited by immunizing rabbits with an elastase degradation product containing kringles 1-3 (EDP I). This antibody was immunopurified by affinity chromatography on plasminogen-Sepharose and elution with 0.2 M 6-aminohexanoic acid. The eluted antibodies bound [125I]EDP I, [125I]Glu-plasminogen, and [125I]Lys-plasminogen in radioimmunoassays, and binding of each ligand was at least 99% inhibited by 0.2 M 6-aminohexanoic acid. The concentrations for 50% inhibition of [125I]EDP I binding by tranexamic acid, 6-aminohexanoic acid, and lysine were 2.6, 46, and 1730 microM, respectively. Similar values were obtained with plasminogen and suggested that an unoccupied high-affinity lysine binding site was required for antibody recognition. The antiserum reacted exclusively with plasminogen derivatives containing the EDP I region (EDP I, Glu-plasminogen, Lys-plasminogen, and the plasmin heavy chain) and did not react with those lacking an EDP I region [miniplasminogen, the plasmin light chain or EDP II (kringle 4)] or with tissue plasminogen activator or prothrombin, which also contain kringles. By immunoblotting analyses, a chymotryptic degradation product of Mr 20,000 was derived from EDP I that retained reactivity with the antibody. The high-affinity lysine binding site was equally available to the antibody probe in Glu- and Lys-plasminogen and also appeared to be unoccupied in the plasmin-alpha 2-antiplasmin complex. alpha 2-Antiplasmin inhibited the binding of radiolabeled EDP I, Glu-plasminogen, or Lys-plasminogen by the antiserum, suggesting that the recognized site is involved in the noncovalent interaction of the inhibitor with plasminogen.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Topography of the high-affinity lysine binding site of plasminogen as defined with a specific antibody probe. 309 30

Using affinity chromatography, the binding of Lys-plasminogen to fibrinogen, fibrin and the consecutively formed products of their proteolysis was studied. The optimal conditions for this binding were elaborated, and the quantitative parameters of Lys-plasminogen binding to fibrinogen-Sepharose were determined. It was found that the interaction of Lys-plasminogen with fibrinogen- and fibrin-Sepharose is provided for by the lysine-binding sites of the proenzyme molecule. After partial hydrolysis of fibrinogen by plasmin, the amount of adsorbed plasminogen increases and the type of binding changes; part of the proenzyme molecules bind in the presence of 0.003 M 6-aminohexanoic acid, i.e., when lysine-binding sites appear to be blocked. A comparative study of plasminogen binding to fibrinogen fragments was carried out. The resistance of the complexes formed to the effect of 6-aminohexanoic acid and arginine competing for the binding sites was determined. The data obtained testify to the appearance of additional plasminogen-binding sites in the fibrinogen molecule during proteolysis. These sites are complementary for both lysine-and arginine-binding sites of the plasminogen molecule and are localized in the peripheral domains of the fibrinogen molecule.
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PMID:[Plasminogen-binding centers of molecules of fibrinogen, fibrin and products of their proteolysis]. 342 34

To establish a method for radiochemical quality control of [99mTc]plasmin based on the known affinity of plasmin for lysine residues, human [113Sn]plasmin and [99mTc]plasmin formed by different methods were analyzed in an affinityradiochromatographic system of lysine coupled to CNBr-activated sepharosis. From the observed immobilizations of the radioactivity when the plasmin was bound to the lysine-sepharosis, radiochemical purities of radiolabelled plasmin could be calculated. The effects of presence of Sn(II) and tartaric and gentisic acid and the remobilizations induced by 6-aminohexanoic acid were studied.
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PMID:Chemical quality control of [99mTc]plasmin by affinityradiochromatography. 622 Sep 79

p-Aminobenzamidine was covalently attached via a spacer moiety to a microparticulate hydrophilic vinyl-polymer gel (Toyopearl HW65S) and this affinity adsorbent was used for the separation of plasmin and plasminogen by high-performance affinity chromatography. Toyopearl HW65S was alkylated with chloroacetylglycylglycine in dimethyl sulphoxide using methylsulphinyl carbanion as a catalyst, then p-aminobenzamidine was coupled to the carboxyl group of glycylglycine to form an acid amide bond. A column packed with the adsorbent retained both plasmin and plasminogen. Plasminogen was eluted with 6-aminohexanoic acid, a haptenic compound for the lysine-binding sites of plasminogen. For the elution of plasmin, the coexistence of 6-aminohexanoic acid and leupeptin (a competitive inhibitor for plasmin) was necessary. The results indicate a two-site interaction of plasmin with the immobilized ligand, i.e., at the lysine-binding sites and the catalytic site. Fluorometric detection of eluted protein and on-line assay of plasmin activity using a fluorogenic substrate, peptidylmethylcoumarylamide, revealed that effective chromatographic separation of the enzyme could be achieved with high sensitivity (10 micrograms) within 1 h.
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PMID:High-performance affinity chromatography of plasmin and plasminogen on a hydrophilic vinyl-polymer gel coupled with p-aminobenzamidine. 623 38

It was demonstrated that plasminogen and the plasmin heavy chain form a complex with an immobilized fibrinogen fragment E. The E-fragment interacts, in its turn, with the immobilized heavy chain; this interaction is provided for by the lysin binding sites of the plasminogen molecule. The plasmin light chain having no lysin binding sites is specifically absorbed on the immobilized fragment D, whereas the D-fragment--on the immobilized light chain. The elution is caused by arginine or benzamidine; 6-aminohexanoic acid does not affect this interaction. It is assumed that the interaction of plasminogen and plasmin with fibrin is provided for not only by the lysine binding but also by the benzamidine binding sites of the plasminogen molecule.
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PMID:[Interaction of heavy and light chains of plasmin with fibrinogen E and D fragments]. 624 Sep 93

Glu-plasminogen [native plasminogen (Glu-1-Asn-790)], Lys-plasminogen [plasmin-cleaved fragment of plasminogen (Lys-77-Asn-790)] and miniplasminogen [fragment of plasminogen (Val-440-Asn-790)] were all found to interact specifically with immobilized 6-aminohexyl ligands. The interactions apparently are mediated by a single weak lysine-binding site, termed the AH-site, as seen from the patterns of inhibition obtained from frontal-quantitative-affinity-chromatography experiments with 6-aminohexanoic acid and alpha-N-acetyl-L-lysine methyl ester as competing ligands. The AH-site, in contrast with the strong lysine-binding site of Glu-plasminogen and Lys-plasminogen, may prefer ligands not carrying a free carboxylate function and therefore may interact with lysine side chains of proteins. In Glu-plasminogen the AH-site is present, but is apparently only partially free to react. It is suggested that it participates in an intramolecular complex and that an equilibrium state between two Glu-plasminogen forms exists. It is further suggested that binding of the plasminogens to fibrin is mainly determined by the AH-site.
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PMID:The AH-site of plasminogen and two C-terminal fragments. A weak lysine-binding site preferring ligands not carrying a free carboxylate function. 643 91

A new simple and efficient purification method for alpha 2-antiplasmin is described that is based on the interaction between alpha 2-antiplasmin and a fragment from elastase-digested plasminogen constituting the three N-terminal triple-loop structures in the plasmin A-chain (LBSI). After a single-step adsorption of the alpha 2-antiplasmin from plasminogen-depleted plasma to LBSI-Sepharose and elution with 6-aminohexanoic acid, an 80-90% pure preparation with a yield of 50-60% is obtained. The major impurity is fibrinogen, which can easily be removed by gel filtration, and, as a result, a homogeneous fully active alpha 2-antiplasmin preparation is obtained that has the same properties as previously described for alpha 2-antiplasmin. Evidence is put forward that a form of alpha 2-antiplasmin with less affinity for the lysine-binding sites in plasminogen may exist, even in unfractionated plasma.
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PMID:Affinity-chromatographic purification of human alpha 2-antiplasmin. 690 16


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