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:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plasminogen activator inhibitor-1 (PAI-1) inhibits the tissue plasminogen activator (tPA) and urokinase activation of plasminogen to plasmin, a protease of trypsin-like specificity which is involved in a number of processes, including fibrinolysis, matrix degradation and angiogenesis. Both phorbol esters and cAMP elevating compounds have been shown to modulate PAI-1 and tPA expression in endothelial cell culture. HBGF-1 (previously designated endothelial cell growth factor) stimulates endothelial cell growth in vitro and is angiogenic in vivo. We have reported that removal of HBGF-1 from human umbilical vein endothelial cell (HUVEC) media results in an approximately 5-fold increase in PAI-1 mRNA levels and in PAI-1 protein secreted into the media by 20 h. Here we report the effects of HBGF-1 on the phorbol ester and cAMP modulation of HUVEC PAI-1 expression. The phorbol ester PMA induced an approximate 5-fold increase in PAI-1 mRNA levels at 4 h, which returned to base line by 20 h, with or without HBGF-1 present in the media. This increase in PAI-1 mRNA levels was mediated by an increase in PAI-1 gene transcription and was abated in the presence of cycloheximide. Treatment of cells with the adenylate cyclase activator forskolin or the phosphodiesterase inhibitor HL 725, in the presence of HBGF-1 or immediately after its withdrawal, decreased PAI-1 mRNA levels and protein secreted into the conditioned media by 20 h. However, forskolin or HL 725 addition had little or no effect on PAI-1 mRNA when added 20 h after HBGF-1 withdrawal. Both the PMA and HBGF-1 modulation of PAI-1 were abolished by treatment with the protein kinase inhibitor H-7. Treatment of HUVEC with HBGF-1 had no acute effect on intracellular inositol phosphate hydrolysis or cAMP levels. Further studies on intracellular pathways involved in HBGF-1 modulation of PAI-1 will enhance our understanding of the role these factors play in cellular proliferation and angiogenesis.
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PMID:Heparin-binding growth factor-1 modulation of plasminogen activator inhibitor-1 expression. Interaction with cAMP and protein kinase C-mediated pathways. 170 36

We have recently demonstrated that many cancer cell lines produce a novel trypsinogen isoenzyme called tumor-associated trypsinogen 2 (TAT-2). It was found during a search of the target protease for tumor-associated trypsin inhibitor (TATI). We now show that degradation of subendothelial cell extracellular matrix (ECM) by four different cell lines (COLO 205 colon carcinoma, K-562 erythroleukemia, CAPAN-1 pancreatic carcinoma, and HT 1080 fibrosarcoma) can be partially inhibited by TATI or neutralizing trypsin antibodies. When cells were cultured in serum-free medium on ECM, TATI and trypsin antibodies inhibited the release of immunoreactive fibronectin fragments from ECM by 47-54 and 40%, respectively. Degradation of isotopically labeled ([3H]serine, [3H]proline, and [35S]sulfate) ECM was also significantly prevented by TATI. At its maximum, it exerted a 57% inhibition on the degradation of [3H]serine-labeled ECM. Plasminogen added exogenously to the culture medium further potentiated the proteolysis of ECM. Interestingly, addition of enteropeptidase, an activator of TAT-2, also enhanced cell-mediated proteolysis as assessed by degradation of purified fibronectin coated onto the surface of wells. Immunoblot analysis showed that enteropeptidase-mediated proteolysis generated a pattern of fibronectin fragments similar to that obtained by digestion of purified fibronectin by TAT-2. These results demonstrate the existence of a proteolytic system in tumor cells which is dependent on the activation of TAT-2. We suggest that TAT-2 is involved in a protease cascade-stimulating tumor cell invasion and degradation of extracellular matrix.
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PMID:Tumor-associated trypsin participates in cancer cell-mediated degradation of extracellular matrix. 200 30

Slow and fast contracting muscles differ in their innervation and electrophysiological properties as well as in their regenerating potentialities. The purpose of the present work was to investigate the expression of plasminogen activators and its possible relation to each type of muscle. Slow (Soleus) and fast (Extensor Digitorum Longus) muscles were obtained from white Wistar rats. Before sectioning the muscles, the euthanized rats were perfused with cold phosphate buffer saline to avoid interference by circulating proteases and inhibitors. Muscle extracts were pounded in an ice-cold Potter tube. Plasminogen activators (PAs) were assayed by fibrin zymography and by both liquid and solid-phase fibrin spectrophotometric assays for the detection of PAs activity. Both urokinase (uPA) and tissue-type plasminogen activator (tPA) activities corresponding to proteins of 38 kDa and 65 kDa molecular masses, were detected in the extracts. Slow muscles contained higher amounts of both activators than fast muscles, but the relative amount of uPA was higher in both types of muscles. In addition, the characteristics of each type of extracts differed somewhat: the fast muscle activity curve was typical of an accelerating process, while the slow muscle curve showed an activity probably related to already formed plasmin or to some other trypsin-like enzyme. These results suggest that the amount of plasminogen activators could be a new criterion of discrimination between slow and fast skeletal muscles.
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PMID:Slow and fast rat skeletal muscles differ in their plasminogen activator activities. 211 33

Plasminogen activator (PA) activity was identified in the conditioned medium of two human renal carcinoma cell lines, Cur and Caki-1. PA activity of medium, following chromatography on Con A-Sepharose, was divided into effluent and eluate fractions, the latter obtained after elution with methyl mannoside. The ratio of PA activity in effluent:eluate was 90:10 for Caki-1 and 60:40 for Cur. The PA of both effluent fractions and the Caki-1 eluate fraction was of the urokinase (UK) type. Identification rested on molecular weight determination by zymography (major component with Mr 52,000 and a less prominent component of 93,000), lack of binding to fibrin, inhibition by anti-UK antibodies, and lack of inhibitory effect of anti-tissue type PA (TPA) antibodies or the Erythrina trypsin inhibitor, which inhibits TPA but not UK. PA of the Cur eluate fraction gave a more complex pattern in that it bound significantly to fibrin (like TPA), was completely inhibited by both anti-UK and anti-TPA antibodies, but was unaffected by Erythrina trypsin inhibitor. These results raise the possibility of an unusual PA-like enzyme that immunologically cross reacts with anti-UK and anti-TPA. Most of the PA of both cell lines was secreted in a latent form that could be activated by trypsin treatment. The latency appears to result largely from secretion of urokinase proenzyme, which is consistent with the Mr 52,000 of the major PA species and the insensitivity to diisopropyl fluorophosphate inhibition prior to trypsin activation. However, in addition, a UK binding component was found in the conditioned medium, which produced an Mr 93,000 component by reaction with UK.
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PMID:Characterization of plasminogen activator from two human renal carcinoma cell lines. 241 48

Activity of peritoneal plasminogen activator and its regulation by dextran and other macromolecules that clinically suppress postoperative adhesions was studied. Plasminogen activator activity was assayed by a two-stage globinolytic assay that monitors formation of plasmin, as well as by cleavage of a chromogenic peptide substrate (S-2444) in the presence of aprotinin (Trasylol). Plasminogen activator activity was located on the outer surface of human peritoneum. Incubation of peritoneal tissue with buffer in vitro (conditioning) prompted release of plasminogen activator into the conditioning medium. The released plasminogen activator formed a single band on sodium dodecyl sulfate-gel electrophoresis at an apparent molecular weight of 174,000 and was markedly suppressed by antiserum raised against human melanoma tissue-type plasminogen activator. Nonspecific proteolytic activity did not accumulate in the medium during conditioning. The presence of dextran 80 during conditioning of peritoneum reversibly suppressed tissue-bound plasminogen activator activity and reduced plasminogen activator activity in the spent medium. A similar inhibition of peritoneal plasminogen activator was induced by dextran 500, methyl cellulose, and polyvinylpyrrolidone. Dextran, when added to the medium after conditioning, had no direct inhibitory effect on plasminogen activator activity. Dextran did not induce peritoneal production of inhibitor(s) of trypsin, chymotrypsin, or urokinase. On the basis of these findings, two possible mechanisms for the effect of viscous polymers in the reduction of adhesion formation are proposed. These mechanisms consider the importance of peritoneal tissue-type plasminogen activator for removal of fibrin clots and suggest that polymer coating either prevents the shedding of plasminogen activator into the abdominal cavity or reduces the access of fibrin clots to the serosal surfaces.
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PMID:Effect of viscous macromolecules on peritoneal plasminogen activator activity: a potential mechanism for their ability to reduce postoperative adhesion formation. 245 68

Plasminogen activator activity was determined in human follicular fluids (FFs) obtained during in vitro fertilization procedures. The fibrinolytic activity of plasminogen activator was significantly higher in fluids from follicles that contained oocytes that were later found to fertilize in vitro (group F) as compared with fluids from follicles that contained oocytes that failed to fertilize (NF). To assess whether this difference in overt plasminogen activator activity reflects differences in conversion of an inactive, latent plasminogen activator to the active enzyme, the ability of exogenous trypsin to enhance plasminogen activation was measured. The plasminogen-dependent hydrolysis of the chromogenic substrate S-2444 in presence of trasylol (Bayer, Leverkusen, Germany) was taken as a measure of plasminogen activator activity in these experiments. No activity was found in untreated FFs, while exposure to trypsin resulted in emergence of marked plasminogen activator activity. In addition, FFs exhibited trasylol-sensitive chromogenic activity indicative of serine-protease activity. Both the plasminogen activator and serine-protease levels after tryptic activation were significantly higher in NF than in F samples. Thus, while F samples have most of their plasminogen activator in an active form, NF samples have most of their plasminogen activator in a latent, trypsin-activatable form. Follicular fluids also contain inhibitory activities toward plasmin and trypsin. The inhibition of these enzymes correlates positively with the latency of plasminogen activator. These results suggest a direct relationship between the ability of oocytes to fertilize and the overt to latent plasminogen activator activity ratios in the FFs.
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PMID:Human follicular fluid protease and antiprotease activities: a suggested correlation with ability of oocytes to undergo in vitro fertilization. 252 54

We examined activities of procoagulant and fibrinolysis in homogenate of leukemic cells. Procoagulant activity (PCA) was increased in patients with acute myelocytic leukemia (AML) and acute promyelocytic leukemia (APL), but it was significantly decreased in patients with chronic myelocytic leukemia (CML) and adult T cell leukemia. In CML, PCA was increased in the blastic phase. Plasminogen activator activity (PLGAA) was also increased in patients with AML, APL and acute lymphocytic leukemia (ALL) associated with disseminated intravascular coagulation (DIC). Elastase-like activity, trypsin-like activity and chymotrypsin-like activity (CTLA) were increased in those with myelocytic leukemia, but they were low in those with lymphocytic leukemia. PCA, PLGAA and CTLA were significantly higher in patients with DIC than in those without DIC. Measurement of procoagulant and fibrinolytic activity in leukemic cells homogenate may be useful not only for studying hemostatic abnormalities but also for classification of leukemic cells.
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PMID:[Activity of procoagulant and fibrinolysis in homogenate of leukemic cells]. 259 44

The turnover of basement membrane macromolecules in injured skeletal muscle has not been studied in contrast to other biologic systems undergoing remodeling. Plasminogen activators and other neutral proteases that are able to degrade these basement membrane macromolecules are secreted by cultured muscle cells. We sought to determine if locally released plasminogen activators could act on basement membrane components. Such degradation might be implicated in the disadhesion of nerve from muscle after motor nerve denervation. To test this hypothesis, we first undertook a study of the sensitivity of muscle extracellular matrix antigens following in vitro exposure to various proteases on frozen muscle sections. Fibronectin was found to be most sensitive, followed by type IV collagen and laminin. Of serine proteases, trypsin was the most active but was not selective, digesting matrix and sarcoplasmic components alike in less than 30 min. Purified urokinase was inactive unless plasminogen (also inactive alone) was previously added to tissue sections, at which time only matrix antigens were digested. Little if any observable degradation of sarcoplasmic proteins took place under these conditions. Using a highly sensitive and selective assay, we found that plasminogen activators were present in muscle tissue and increased 8- to 10-fold after 10 days of denervation. Using an extract of denervated muscle in the presence of plasminogen, we observed degradation of matrix antigens. No degradation was observed with control muscle extract. We next evaluated the degradation of these antigens in denervated muscle during a temporal study. The results, analyzed by quantitative image analysis, indicates that with increasing time after denervation a marked decrease of fibronectin and type IV collagen, followed by laminin occurred but, again, only in the present of plasminogen. These results indicate a selective sensitivity of basement membrane antigens of muscle and a role for plasminogen activators in the degradation of these adhesive basement membranes macromolecules after denervation.
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PMID:Degradation of muscle basement membrane zone by locally generated plasmin. 294 9

Plasminogen activator (PA) is an estradiol-inducible enzyme and therefore a potential marker for a functional estradiol receptor (ER) in human breast carcinomas. In this investigation tissue-type PA (t-PA) correlated significantly with both ER and progesterone receptors (PR) in human breast carcinomas. In contrast, neither total PA activity nor urokinase-like PA showed any significant correlation with either ER or PR. Other proteases such as a trypsin-like protease, a chymotrypsin-like protease, and cathepsin B also showed no correlation with ER and PR. It was concluded that the t-PA form of PA may be a marker for a functional ER in breast carcinoma and thus be of value in predicting hormone-dependent breast cancers.
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PMID:Tissue-type plasminogen activator in breast cancer: relationship with estradiol and progesterone receptors. 309 95

Plasminogen activator was previously shown to be induced by UV light in human cells with low capacity to repair UV-induced DNA lesions. We now show that in human fetal fibroblasts UV light enhanced the two mRNA species coding for the urokinase-type plasminogen activator (uPA) and the tissue-type plasminogen activator, but immunological analysis revealed exclusively uPA activity. Several independent and complementary experiments indicated that induction of uPA was mediated, apparently entirely, through a UV-induced, secreted protein (UVIS) in the growth medium of irradiated cells. First, elevation of uPA mRNA after irradiation was severely blocked by cycloheximide. Second, replacement of conditioned medium in irradiated cells while the rate of plasminogen activator induction was maximal rapidly and completely stopped any further increase in uPA activity. Third, addition of the same removed conditioned medium to nonirradiated cells mimicked UV light in enhancing the level of uPA activity as well as that of uPA mRNA. Fourth, UVIS activity was completely lost by treating the conditioned medium with trypsin but not with nucleases. Kinetic measurements indicated that the accumulation of UVIS rather than the induction of uPA by UVIS conferred the rate-limiting step in the overall process of uPA induction. Both UV light and UVIS acted synergistically with inhibitors of DNA repair for uPA induction. Based on these results, a model is proposed implicating relaxation of DNA torsional stress of an as yet undefined DNA sequence(s) in the induction of UVIS, which is then responsible for activation of the uPA gene.
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PMID:Induction of urokinase-type plasminogen activator by UV light in human fetal fibroblasts is mediated through a UV-induced secreted protein. 310 44


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