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)

Serine protease inhibitors have important regulatory roles in angiogenesis, intravascular fibrinolysis, wound healing, and cell migration. In this study, the extracellular matrix secreted by cultured human keratinocytes, foreskin fibroblasts, and SV-40-transformed human skin fibroblasts was analyzed for serine protease inhibitors by substrate reverse zymography. We found that the extracellular matrix deposited by these cells contained three inhibitors (M(r) 33,000, 31,000, and 27,000). These inhibitors protected the degradation of gelatin by trypsin and elastase, and of casein by plasmin. In contrast, the gelatinolytic activities of thermolysin and papain were not inhibited. Compared to untreated cells, cells treated with phorbol 12-myristate 13-acetate showed a two- to 10-fold increase in the expression of these inhibitors. Cycloheximide and actinomycin D decreased the cellular expression of these inhibitors, suggesting the involvement of de novo protein and mRNA synthesis. Antitrypsin activity of these inhibitors was resistant to heat and sodium dodecylsulfate, but was lost after reduction of disulfide bonds. The inhibitors bound specifically to trypsin and could be eluted from a trypsin column in active form. Collectively, these data suggest that the extracellular matrix deposited by keratinocytes and dermal fibroblasts contains active serine protease inhibitors.
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PMID:Partial characterization of matrix-associated serine protease inhibitors from human skin cells. 786 Oct 6

When porcine endothelial cells in culture are incubated in the presence of human platelets, a 90kDa neutral proteinase activity is generated on casein gel (PECAP-Platelet Endothelial Cell Activated Protease). This activity was undetected when platelet extract or serum free EC conditioned medium were analysed under similar conditions. The optimum pH, isoelectric point, molecular weight and inhibitory profile of this activity were similar to Glu-plasmin. However, the low plasminogen content (less than 50ng/ml) in the conditioned medium of endothelial cells incubated with platelet could not contribute alone to this activity and the presence of a plasmin potentiating factor was suggested. This factor was separated from plasminogen by lysine-Sepharose chromatography.
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PMID:Fibrinolysis potentiating activity following endothelial cells-platelet interaction. 786 75

Clots formed from platelet rich plasma were found to be lysed more readily by low concentrations of pro-urokinase (pro-UK) than clots formed from platelet poor plasma. This was not a non-specific effect since the reverse occurred with tissue plasminogen activator. A mechanical explanation due to platelet-mediated clot retraction was excluded by experiments in which retraction was inhibited with cytochalasin B. Therefore, a platelet-mediated enzymatic mechanism was postulated to explain the promotion of fibrinolysis. Casein autography of isolated platelets revealed a approximately 90 kDa band of activity which comigrated with plasma prekallikrein (PK)/kallikrein, a known activator of pro-UK. Furthermore, treatment of platelets with plasma PK activator (PPA), consisting essentially of factor XIIa, induced activation of pro-UK and of chromogenic substrate for kallikrein (S-2302). This activity corresponded to approximately 40-200 pM kallikrein per 10(8) washed and gel filtered platelets per ml. The activation of pro-UK by PPA-pretreated platelets was dose-dependent and inhibited by soybean trypsin inhibitor but not by bdellin, a specific inhibitor of plasmin, nor by the corn inhibitor of factor XIIa. Kinetic analysis of pro-UK activation by kallikrein showed promotion of the reaction by platelets. The KM of the reaction was reduced by platelets by approximately 7-fold, while the kcat was essentially unchanged. In conclusion, PK was shown to be tightly associated with platelets where it can be activated by factor XIIa during clotting. The activation of pro-UK by platelet-bound kallikrein provides an explanation for the observed platelet mediated promotion of pro-UK-induced clot lysis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Platelet-bound prekallikrein promotes pro-urokinase-induced clot lysis: a mechanism for targeting the factor XII dependent intrinsic pathway of fibrinolysis. 802

Hydrolysis of collagen molecules in the presence of collagenolytic proteases A and C from the king crab has been studied by electrophoresis. Both proteases are shown to hydrolyze effectively type I and III collagens, patterns of the products differing for the proteases A and C. The thermal denaturation of the type I collagen increased the effectiveness of the enzymatic hydrolysis. The crab collagenolytic proteases catalyze the hydrolysis of such proteins as bovine serum albumin, ovalbumin, horse cytochrome c, mouse immunoglobulin G, casein and human fibrinogen, only elastin being resistant. The mechanisms of the fibrinogen cleavage differ not only for the proteases A and C but also for plasmin, whereas the efficiencies in all the cases are similar.
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PMID:[Hydrolysis of proteins by collagenolytic proteinases from the king crab]. 815 81

Bovine plasmin (EC 3.4.21.7) activity was measured on H-D-valyl-L-leucyl-L-lysyl-4-nitroanilide and acid casein in the presence of native and heat-denatured beta-lactoglobulin (denatured at 100 degrees C for 15 min before being mixed with plasmin solutions). Native or denatured beta-lactoglobulin was then heated with plasmin at 60 degrees C for 15 min. Enzyme activity again was estimated after this mild heat treatment. Native and denatured beta-lactoglobulin inhibited the action of plasmin on H-D-valyl-L-leucyl-L-lysyl-4-nitroanilide and casein. The mild heat treatment (60 degrees C for 15 min) caused stronger inhibition of the activity of plasmin against casein and the synthetic substrate. For H-D-valyl-L-leucyl-L-lysyl-4-nitroanilide, inhibition was competitive in unheated mixtures, but heating beta-lactoglobulin with plasmin changed inhibition type to mixed. This change suggests a heat-dependent interaction between plasmin and beta-lactoglobulin. Native beta-lactoglobulin was more inhibitory of plasmin's action against casein than was denatured beta-lactoglobulin. The converse was observed when plasmin activity was measured with the synthetic substrate.
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PMID:Inhibition of plasmin by beta-lactoglobulin using casein and a synthetic substrate. 827 Jun 80

The expression of plasminogen activators and inhibitors was examined in denuded arteries. Within 5 days, smooth muscle cells (SMCs) on the luminal surface expressed the mRNA for tissue-type plasminogen activator (TPA), urokinase type plasminogen (UPA), the receptor for UPA (UPAR), and plasminogen activator inhibitor type-1 (PAI-1). Similar results were seen after 8 days. Six weeks later, only TPA mRNA was still expressed by SMCs on the luminal surface. En face casein zymograms revealed a net fibrinolytic activity in areas covered with luminal SMCs. Reverse zymography showed no antifibrinolytic activity in these zones. Quiescent endothelial cells did not express TPA, UPA, UPAR, or PAI-1 mRNA. Regenerating endothelium at the wound edge strongly expressed TPA. UPA, and UPAR, as well as PAI-1. UPA and UPAR expression was highly restricted to cells at the wound edge and was not present elsewhere. En face zymography showed no plasmin activity in endothelialized areas, and reverse zymography showed a net fibrinolytic activity in endothelialized zones. These results suggest that plasminogen activator and inhibitor expression correlates with the migration of both SMCs and endothelial cells into an arterial wound.
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PMID:Migration of arterial wall cells. Expression of plasminogen activators and inhibitors in injured rat arteries. 859 99

A longitudinal study was carried out on samples of bulk tank milk collected from 200 farms for 12 mo to evaluate SCC, plasmin and plasminogen activities, psychrotrophic bacteria count, and protein quality in milk and to examine the proteolytic effects of plasmin on milk proteins. Herds were selected randomly from client lists of two dairies to create four groups based on milk SCC of the month before the study; herds were reassigned monthly to one of four groups based on SCC for that month. Overall means were 3.73% fat, 3.13% protein by infrared analysis, 3.16% protein by Kjeldahl analysis, 2.42% casein percentage, 4.65% lactose, 5.43 cells/ml of log SCC, 1.13 U of plasmin, 45.6 U of plasminogen, and log 2.86 cfu/ml of psychrotrophic bacteria. The ANOVA showed a significant effect of month on all factors except SCC, which was fixed by the experimental design. Plasmin and plasminogen activities were high from December to May. Plasmin activities and psychrotroph counts were significantly higher for the high SCC group. Casein percentage and number were significantly higher for the low SCC group.
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PMID:Factors affecting herd milk composition and milk plasmin at four levels of somatic cell counts. 859 3

The tripeptide compounds, Glu-Arg-Pro-amide (ERPm), D-Pro-Thr-Trp-amide (dPTWm) and thioproline-Thr-Trp (tPTW), were obtained by screening of synthetic peptides for growth-inhibitory activity toward cultured transformed cells. The effects of these peptide compounds on proteases were investigated and the results showed that these compounds enhanced the amidolytic activity of serine proteases despite the fact that each reaction was carried out under optimal conditions. ERPm stimulated the activities of trypsin, chymotrypsin, thrombin, plasmin urokinase and elastase. dPTWm also showed similar effects except that toward chymotrypsin. tPTW elevated the activity only of trypsin, chymotrypsin and thrombin. Stimulation of trypsin activity by these compounds was also confirmed by using casein as a substrate. None of these compounds affected the amidolytic activities of metalloproteinases (MMP-1 and MMP-9), cysteine proteinases (m- and mu-calpains, cathepsin B and papain) or an exopeptidase (leucine aminopeptidase). The activation was at least partly due to the stabilization of the catalytic activity of proteases as well as prevention of autolysis.
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PMID:Enhancement of catalytic activities of serine proteases by tripeptides compounds. 863 1

Borrelia burgdorferi binds human urokinase plasminogen activator (uPA), which cleaves plasminogen (Pgn) to plasmin. The ability of other Borrelia species to bind uPA, Pgn, or both was investigated. Borrelia coriacae, Borrelia garinii, Borrelia parkeri, Borrelia anserina, and Borrelia turicatae were compared with infectious and noninfectious B. burgdorferi isolates. All Borrelia species lacked endogenous proteases capable of digesting casein, but all species bound human uPA and Pgn, generating Pgn-dependent proteolytic activity. There were no significant differences in the amount of plasmin, Pgn, or uPA bound per spirochete of the different species. On unfixed borreliae, fluorochrome-conjugated uPA bound to all species. Early binding was at the terminus of B. burgdorferi, whereas diffuse binding was observed on B. coriacae, B. garinii, B. parkeri, and B. turicatae. These studies demonstrate that binding of human uPA and Pgn to borreliae occurs on multiple species with apparent differences in surface distribution.
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PMID:Binding of human urokinase type plasminogen activator and plasminogen to Borrelia species. 865 20

Matrigel, a basement membrane (BM) extract of the Engelbreth-Holm-Swarm (EHS) sarcoma, used in tumor invasion assays, was found to contain plasminogen. Plasminogen was identified, using Western blot analysis and casein zymograms, by comparison with human plasminogen. matrigel contained approximately 20-100 ng of plasminogen per 100 micrograms of protein as determined by these assays. Matrigel reconstitution and incubation at 37 degrees C caused activation of plasminogen, which was serine protease dependent and involved tissue plasminogen activator (tPA) as an anti-tPA antibody which inhibited activation. This reconstitution and incubation also caused leupeptin-inhibitable degradation of Matrigel components as assessed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Degradation of the BM extract copolymerized in zymograms was caused by human plasminogen and plasminogen in the Matrigel. Maximal plasmin activity, following incubation of Matrigel at 37 degrees C for 16 h, was equivalent to approximately 10 ng of purified plasmin using the plasmin substrate D-Val-Leu-Lys p-nitroanilide. matrigel, therefore, contained all the components of the plasmin-generating system, including plasminogen. The plasmin generated degraded Matrigel components and exogenous substrates. Our data suggest that, since this tumor BM acts as a reservoir for enzymes of the plasmin-generating system, caution should be taken by investigators interpreting data concerning the effects of Matrigel on cell behavior and, in particular, cellular invasion.
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PMID:Identification of plasminogen in Matrigel and its activation by reconstitution of this basement membrane extract. 892 33


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