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

Transforming growth factor-beta (TGF beta) is produced by most cultured cells in an inactive form. Potential activation mechanisms of latent TGF beta were studied using fibroblastic (NRK-49F and AKR-MCA) cell-conditioned medium as a model. Active TGF beta was monitored by radioreceptor and soft agar assays as well as by antibody inhibition and immunoprecipitation. Little or no TGF beta was detected in untreated conditioned medium. Treatment of the medium with extremes of pH (1.5 or 12) resulted in significant activation of TGF beta as shown by radioreceptor assays, while mild acid treatment (pH 4.5) yielded only 20-30% of the competition achieved by pH 1.5. In an effort to define more physiological means of TGF beta activation, the effects of some proteases were tested. Plasmin and cathepsin D were found to generate 25-kD bands corresponding to the active form of TGF beta as shown by immunoprecipitation analysis of radiolabeled cell-conditioned medium. Plasmin treatment of the medium resulted in activity that was quantitatively similar to that of mild acid treatment as measured by radioreceptor and soft agar assays. In addition, the plasmin-generated activity was inhibited by anti-TGF beta antibodies. Sequential treatments of AKR-MCA cell-conditioned medium with mild acid followed by plasmin or plasmin followed by mild acid gave activation comparable to either treatment alone. The data suggest that conditioned medium may contain at least two different pools of latent TGF beta. One pool is resistant to mild acid and/or plasmin and requires strong acid or alkali treatment for activation. A second pool is activated by mild pH change and/or plasmin. Activation of this form of latent TGF beta may take place by dissociation or proteolytic digestion from a precursor molecule or hypothetical TGF beta-binding protein complex.
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PMID:Proteolytic activation of latent transforming growth factor-beta from fibroblast-conditioned medium. 296 99

An inactive form of human urinary kallikrein (inactive HUK) was highly purified from fresh urine collected from healthy men. Inactive HUK was separated from the active kallikrein (HUK) initially presents in the urine by affinity chromatography on a column of aprotinin immobilized on Sepharose 4B and further purified by gel filtration, ion-exchange chromatography and immunoaffinity chromatography on an anti-HUK antibody immobilized Sepharose 4B column. Inactive HUK was rapidly activated by a trace amount of trypsin. While, plasmin, urokinase, thrombin and chymotrypsin caused no activation of inactive HUK. The molecular weights of inactive HUK and HUK were estimated to be 4.8 X 10(4) and 4.5 X 10(4), respectively. The molecular weight of active HUK generated from inactive HUK by the action of trypsin (HUK'') was almost the same as that of HUK. The mobility of inactive HUK was slightly slower than that of HUK on both immunoelectrophoresis and polyacrylamide gel disc electrophoresis. On the other hand, the electrophoretic mobility of HUKK'' was almost the same as that of HUK. These two types of active HUK had no significant difference in the Km values for H-Pro-Phe-Arg-MCA hydrolysis and inhibition profiles by various protease inhibitors and anti-HUK antibody. Inactive HUK was unable to be measured by the direct radioimmunoassay (RIA) but HUK" generated by the action of trypsin could be measured by the RIA.
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PMID:An inactive form of kallikrein in human urine. 354 16

Electrophoretic analysis of plasminogen activators from pig heart, human uterus, human plasma and human melanoma cells was performed in SDS-polyacrylamide gradient slab gels containing plasminogen and casein. Direct visualization of activator activity bands in polyacrylamide gels was achieved after removal of SDS, incubation in buffer, and staining with Coomassie brilliant blue. Tissue activator extracted from pig hearts displayed a molecular weight of 72000 and migrated similarly to activator secreted by human melanoma cells and to one activator component present in extracts of human uterus. Immunoadsorption experiments with melanoma cell activator antiserum indicated that these 72-kDa activators are all related immunologically. Human uterus also contained a second activator component with a molecular weight 55000, which migrated similarly to a higher molecular weight component of urokinase and cross-reacted with urokinase antiserum. We conclude that the 72-kDa uterine activator component represents a tissue activator and the 55-kDa component represents a urokinase-like activator. A euglobulin solution from venous occlusion plasma displayed multiple bands of plasmin activity in the Mr range 85000-96000. Two activator components were also present, one of Mr 72000 and another of Mr 62000. The 72-kDa euglobulin activator was adsorbed by MCA antiserum, and we conclude that this component represents vascular activator. The 62000 activator also had weak plasminogen-independent caseinolytic activity and was not affected by either melanoma cell activator or urokinase antisera. Conclusions concerning its identity cannot be made at this time.
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PMID:Comparative electrophoretic analysis of human and porcine plasminogen activators in SDS-polyacrylamide gels containing plasminogen and casein. 634 80

3-Methylcholanthrene-induced tumor was challenged with a low molecular synthetic protease inhibitor, [N,N-dimethylcarbamoylmethyl 4-(4-guanidinobenzoyloxy)-phenylacetate] methanesulfate. This drug at a dosage of 10 mg/kg or 20 mg/kg was administered by ip injection to 20 mice each harboring a solitary tumor twice daily for 10 weeks. This protease inhibitor significantly inhibited tumor growth and prolonged the survival time of the tumor-bearing mice (P less than 0.001). The results suggest the involvement of kinin-forming proteases, such as trypsin, plasmin and kallikrein, in the tumor growth.
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PMID:Inhibition of growth of 3-methylcholanthrene-induced mouse skin tumor by protease inhibitor [N,N-dimethylcarbamoylmethyl 4-(4-guanidinobenzoyloxy)-phenylacetate] methanesulfate. 734 42

An arginine specific protease, Sp-protease, was purified by column chromatography from freeze-dried Spirulina platensis using a five-step process. Purified Sp-protease has a molecular weight of 80 kDa. It hydrolyzed the synthetic substrates containing arginine residue in the P1 position but did not hydrolyze synthetic substrates containing other amino acid residues, including lysine residue in the P1 position. Among the synthetic substrates tested, a substrate of plasminogen activator (Pyr-Gly-Arg-MCA) was hydrolyzed most effectively with the enzyme (Km = 5.5 x 10(-6) M), and fibrin gel was solubilized via activation of intrinsic plasminogen to plasmin with the enzyme. Activity was inhibited completely with camostat mesilate (Ki = 1.1 x 10(-8) M) and leupeptin (Ki = 3.9 x 10(-8) M) but was not inhibited with Nalpha-tosyl-L-lysine chloromethyl ketone (TLCK). The optimum pH of the enzyme has a range of pH 9.0 to pH 11.0. The optimum temperature was 50 degrees C; the enzyme was stable at 0-50 degrees C.
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PMID:An arginine specific protease from Spirulina platensis. 1618 1

A single-site mutant (M5) of native urokinase plasminogen activator (prouPA) induces effective thrombolysis in dogs with venous or arterial thrombosis with a reduction in bleeding complications compared to tPA. This effect, related to inhibition of two-chain M5 (tcM5) by plasma C1-inhibitor (C1I), thereby preventing non-specific plasmin generation, was augmented by the addition of exogenous C1I to plasma in vitro. In the present study, tPA, M5 or placebo +/- C1I were administered in two rat stroke models. In Part-I, permanent MCA occlusion was used to evaluate intracranial hemorrhage (ICH) by the thrombolytic regimens. In Part II, thromboembolic occlusion was used with thrombolysis administered 2 h later. Infarct and edema volumes, and ICH were determined at 24 h, and neuroscore pre (2 h) and post (24 h) treatment. In Part I, fatal ICH occurred in 57% of tPA and 75% of M5 rats. Adjunctive C1I reduced this to 25% and 17% respectively. Similarly, semiquantitation of ICH by neuropathological examination showed significantly less ICH in rats given adjunctive C1I compared with tPA or M5 alone. In Part-II, tPA, M5, and M5+C1I induced comparable ischemic volume reductions (>55%) compared with the saline or C1I controls, indicating the three treatments had a similar fibrinolytic effect. ICH was seen in 40% of tPA and 50% of M5 rats, with 1 death in the latter. Only 17% of the M5+C1I rats showed ICH, and the bleeding score in this group was significantly less than that in either the tPA or M5 group. The M5+C1I group had the best Benefit Index, calculated by dividing percent brain salvaged by the ICH visual score in each group. In conclusion, adjunctive C1I inhibited bleeding by M5, induced significant neuroscore improvement and had the best Benefit Index. The C1I did not compromise fibrinolysis by M5 in contrast with tPA, consistent with previous in vitro findings.
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PMID:Mutant prourokinase with adjunctive C1-inhibitor is an effective and safer alternative to tPA in rat stroke. 2177 64