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

---

Query: EC:3.4.21.7 (plasmin)
9,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human embryonic lung (HuEL) cells in culture produce large amounts of the enzyme, plasminogen activator, and thus generate substantial amounts of active plasmin. Despite the presence of plasmin, however, HuEL cells grow in ordered, flattened, adherent sheets. It seemed of interest to characterize protease inhibitors that might be present in HuEL cultures and which might account for this apparent contradiction. This paper reports the isolation and purification of the major serine protease inhibitor in 5-day serum-free conditioned medium (CM) from HuEL cells, and the purification of an identical molecule from fetal bovine serum (FBS). Both the CM-derived inhibitor and the FBS-derived inhibitor are identical with fetuin, the major glycoprotein of FBS. The CM-derived inhibitor is apparently derived from the FBS used to supplement the growth medium of HuEL cells between serum-free CM collection periods. It is not labeled metabolically with 3H-leucine. Its electrophoretic behavior is indistinguishable from that of standard fetuin in SDS-PAGE, non-SDS basic pH,PAGE, and isoelectric focusing. The CM-derived inhibitor and standard fetuin inhibit trypsin and plasmin with similar efficiencies, but neither inhibits chymotrypsin, pancreatic elastase, or plasminogen activator. They are immunologically indistinguishable. The suggestion is made that fetuin, and possibly other protease inhibitors present in HuEL cell cultures, may be concentrated locally by HuEL cells and gradually released back into the medium in the absence of serum. These molecules may serve to protect HuEL cells against proteases they generate.
...
PMID:Isolation of the major serine protease inhibitor from the 5-day serum-free conditioned medium of human embryonic lung cells and demonstration that it is fetuin. 617 91

Activated porcine Factor IX is irreversibly inhibited by an active site histidine-directed serine protease inhibitor, dansyl-glutamyl-glycyl-arginyl-chloromethylketone (DEGR-CK). The kinetics of inhibition are second order up to inhibitor concentrations of 10(-5) M. The apparent second-order rate constant (in 0.20 M NaCl, pH 8.0) is 1.7 X 10(4) M-1 min-1, which is considerably lower than values reported for Factor Xa, thrombin, plasmin, and kallikrein. Reaction of increasing concentrations of DEGR-CK with Factor IXa, followed by analysis of residual enzymatic activity, yields 1.2 mol DEGR-CK/mol protein, indicating 1:1 stoichiometry for the DEGR-CK/Factor IXa interaction. DEGR-Factor IXa is a potent anticoagulant in vitro. A concentration of 1 nM causes 50% inhibition of the ability of normal porcine-citrated plasma to correct either Factor VIII- or Factor IX-deficient plasmas (intrinsic pathway factors). In contrast, more than 100 nM DEGR-Factor IXa is required to cause 50% inhibition of Factor VII (extrinsic pathway) or Factor X (common pathway) assays. Activation of porcine Factor VIII:C by thrombin in the presence of DEGR-Factor IXa and phosphatidylcholine-phosphatidylserine vesicles reveals that DEGR-Factor IXa markedly stabilizes the spontaneous loss of Factor VIII:Ca activity as does unmodified Factor IXa [P. Lollar, G.J. Knutson, and D. N. Fass (1984) Blood 63, 1303-1308]. These results suggest that DEGR-Factor IXa incorporates into the intrinsic pathway Factor X-activator enzymatic complex, and also that stabilization of Factor VIII:Ca by this complex is independent of the active site of Factor IXa. Inhibition of Factor IXa by DEGR-CK results in the first reported irreversible active-site-modified derivative of this enzyme. DEGR-CK promises to be a useful reagent in the study of the Factor X activator complex. Conceivably, its specific anticoagulant properties could have future clinical benefit.
...
PMID:Inhibition of activated porcine factor IX by dansyl-glutamyl-glycyl-arginyl-chloromethylketone. 643 27

Patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) experience transient haemostatic defects as a result of adverse changes to their blood components, blood cells and specific coagulation proteins. Aprotinin is a naturally occurring serine protease inhibitor isolated from bovine lung tissue which inhibits kallikrein and plasmin. A high dose aprotinin regimen (aprotinin 280mg loading dose over 20 to 30 minutes after anaesthesia induction followed by 70 mg/h for the duration of the operation and 280mg added to the priming fluid of the CPB circuit) has been used during CPB in order to reduce perioperative bleeding. Recent clinical trials confirm the efficacy of high dose aprotinin in reducing blood loss and transfusion requirements associated with primary cardiac procedures such as coronary artery bypass graft (CABG) or heart valve replacement surgery. High dose aprotinin is also effective in procedures known to possess a high risk for excessive blood loss, such as repeat CABG or heart valve replacement surgery, cardiac surgery in patients with infective endocarditis, or in patients receiving aspirin (acetylsalicylic acid) before surgery. Studies indicate that low dose aprotinin (280mg added to CPB pump prime fluid) is effective in reducing blood loss and transfusion requirements in patients undergoing primary CABG surgery. Additionally, low dose aprotinin regimens (both 280mg added to CPB pump prime fluid and 50% of the high dose regimen) have shown some benefit in repeat CABG surgery; however, more studies are needed to confirm these results. Data from clinical trials indicate that aprotinin is well tolerated. The types and incidences of adverse events reported with aprotinin therapy are generally consistent with those associated with major cardiac surgery, and are not significantly different from those observed in control groups. A trend towards lower graft patency rates, detected by ultrafast computerised tomography (CT), has been observed in aprotinin recipients in 2 US trials. These differences did not reach statistical significance and should be interpreted with caution since the ability of ultrafast CT to determine graft patency has not been validated. Mildly elevated plasma creatinine levels are more commonly observed in aprotinin-treated patients; these changes are transient in the majority of patients. Both high dose and low dose aprotinin regimens (280mg added to CPB pump prime fluid or 50% of the high dose regimen) have reduced blood loss and transfusion requirements in patients undergoing primary and repeat cardiac surgery. The role of aprotinin in paediatric cardiac surgery needs further clarification, while well-designed studies comparing aprotinin with other agents which inhibit fibrinolysis are also awaited with interest.(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:Aprotinin. A review of its pharmacology and therapeutic efficacy in reducing blood loss associated with cardiac surgery. 754 41

PC-3 cells, whose growth is androgen-independent, were shown to be capable of slow proliferation in serum-free medium and in the absence of added growth factor for 7 days. They secreted insulin-like growth factor (IGF)-II but no detectable IGF-I. This IGF-II, although produced in small amounts, plays a role in their proliferation because growth could be inhibited dose dependently by up to 80% in the presence of monoclonal antibodies directed against IGFs or the type 1 IGF receptor. PC-3 cells also secreted IGF binding proteins (IGFBPs) -2, -3, -4, and -6. Immunoblot analysis revealed selective proteolysis of IGFBP-3, yielding fragments of the same molecular size as those generated from IGFBP-3 in vivo. With the addition to the culture medium of a serine protease inhibitor, 4-(2-aminoethyl)-benzenesulfonyl fluoride (Pefabloc-SC), at concentrations < 0.2 mM that were nontoxic to the cells, cell proliferation was dose dependently inhibited up to 80% and, at the same time, proteolysis of the IGFBP-3 secreted by the cells was depressed. Urokinase activity detected in the conditioned media was depressed by Pefabloc, suggesting that the urokinase-type plasminogen activator was involved in the proteolysis of IGFBP-3. In addition, 0.01-5 micrograms/ml plasminogen induced a dose-dependent increase in both proliferation and the proportions of proteolysed IGFBP-3 in the media. The stimulation of proliferation was totally blocked in the presence of anti-type 1 IGF receptor antibody. Recombinant human IGF-II (5-200 ng/ml) added to cell-free medium conditioned by 48 h of culture dose dependently stimulated PC-3 cell proliferation. At concentrations < or = 100 ng/ml, its mitogenic action was potentiated when medium had been conditioned by cells cultured in the presence of plasminogen but inhibited when medium had been conditioned by cells cultured in the presence of Pefabloc. We conclude from these results 1) that IGF-II is involved in the autocrine control of PC-3 cell proliferation via the type 1 IGF receptor; and 2) that this proliferation is directly dependent on IGF-II bioavailability that itself is modulated by the limited IGFBP-3 proteolysis induced, at least in part, by urokinase-type plasminogen activator and plasmin.
...
PMID:Autocrine regulation of cell proliferation by the insulin-like growth factor (IGF) and IGF binding protein-3 protease system in a human prostate carcinoma cell line (PC-3). 758 99

Aprotinin is a nonspecific serine protease inhibitor extracted from bovine lung. It was first used during cardiopulmonary bypass to inhibit plasmin-induced complement activation. By chance significant reductions of blood loss and blood requirements were noted in treated patients. Subsequent investigation showed improved hemostasis to result from protection of platelet adhesive receptors (Gp Ib) at the onset of cardiopulmonary bypass. Without aprotinin the contact system of plasma is massively activated on first passage through the cardiopulmonary bypass circuit. Activation of the intrinsic coagulation pathway causes thrombin formation, which impairs platelet adhesive function. Aprotinin blocks contact activation of the kallikrein system during cardiopulmonary bypass and in synergy with heparin prevents thrombin formation through inhibition of the intrinsic clotting cascade. It is likely that neither thrombin nor platelets become involved in the blood-foreign surface contact activation process in aprotinin-treated patients. The fact that the hemostatic process is affected from the very beginning of cardiopulmonary bypass is substantiated by the fact that low-dose aprotinin therapy (2 x 10(6) KIU aprotinin added to the pump prime) leads to the same preservative effect on Gp Ib receptors and blood loss as continuous high-dose infusion (6 x 10(6) KIU) throughout the whole surgical procedure. In the presence of heparin aprotinin prolongs the activated clotting time and the in vitro activated partial thromboplastin time. This has important implications for heparin dosage. An inhibitory effect on the endothelial cell anticoagulant function may also have consequences during hypothermic low flow and circulatory arrest states.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Aprotinin in perspective. 768 54

We described in a foregoing report findings on serpin, a serine protease inhibitor, newly identified in horseshoe crab (Tachypleus tridentatus) hemocytes and we name it limulus intracellular coagulation inhibitor, LICI (Miura, Y., Kawabata, S., and Iwanaga, S. (1994) J. Biol. Chem. 269, 542-547). This serpin specifically inhibits limulus lipopolysaccharide-sensitive serine protease, factor C. In ongoing studies on limulus serpin, we have found another inhibitor, LICI type-2 (LICI-2), which inhibits not only factor C (k1 = 7.1 x 10(4) M-1 S-1) but also limulus clotting enzyme (k1 = 4.3 x 10(5) M-1 S-1). LICI-2 inhibits mammalian serine proteases, including alpha-thrombin, salivary kallikrein, plasmin, and tissue plasminogen activator. The inactivation of plasmin is the most rapid (k1 = 1.2 x 10(6) M-1 S-1). The purified LICI-2 is a single chain glycoprotein with an apparent M(r) = 42,000. A cDNA for LICI-2 was isolated and the open reading frame coded for a mature protein of 386 amino acids, of which 160 residues were confirmed by peptide sequencing. Although LICI-2 shows significant sequence similarity to the previous limulus serpin, LICI-1 (42% identity), LICI-2 contains a unique putative reactive site, -Lys-Ser-, distinct from that of LICI-1 (-Arg-Ser-). Northern blotting revealed expression of LICI-2 mRNA only in hemocytes, and not in heart, brain, stomach, intestine, coxal gland, and skeletal muscle. The immunoblot of large and small granule components with antiserum against purified LICI-2 suggests that LICI-2 is stored specifically in large granules, as in the case of LICI-1, and is released in response to external stimuli. We propose that the LICIs be classified into a new subfamily of intracellular serpins, regulated secretory serpins.
...
PMID:A limulus intracellular coagulation inhibitor type 2. Purification, characterization, cDNA cloning, and tissue localization. 782 80

Ecotin, a serine protease inhibitor found in the periplasm of Escherichia coli, has been characterized as an extremely potent anticoagulant and reversible tight-binding inhibitor of human factor Xa (FXa). The ecotin gene was cloned by PCR, highly expressed in E. coli, and purified from the E. coli periplasm. The binding of ecotin to FXa was stoichiometric with an equilibrium dissociation constant Ki of 54 pM. The association rate constant was 1.35 x 10(6) M-1 s-1, and the dissociation rate constant, measured in the presence of human leukocyte elastase (HLE) to prevent reassociation of ecotin with FXa, was 6.5 x 10(-5) s-1. Ecotin prolonged clotting time ca. 10-fold at 0.3 microM and at 2 microM in activated partial thromboplastin time and prothrombin time assays, respectively. Ecotin did not effectively inhibit the human plasma proteases thrombin, tissue factor.factor VIIa, factor XIa, activated protein C, plasmin, or tissue plasminogen activator (t-PA); however, it did potently inhibit factor XIIa, plasma kallikrein, HLE, and bovine trypsin and chymotrypsin. Coincubation of ecotin and FXa at 10 microM each resulted in a (ecotin)2.(FXa)2 complex as determined by gel filtration. Dimerization of ecotin alone was measured by fluorescence titration which yielded a Kd of ca. 390 nM. FXa cleaved ecotin slowly at pH 4.0 between M84 and M85. Replacement of the P1 Met84 residue with Arg and Lys led to FXa inhibitors with Ki values of 11 and 21 pM, respectively. The P1 Arg and Lys mutants also significantly inhibited thrombin, factor XIa, activated protein C, plasmin, factor XIIa, kallikrein, and bovine trypsin and chymotrypsin but did not inhibit tissue factor.factor VIIa, t-PA, or HLE.
...
PMID:Ecotin is a potent anticoagulant and reversible tight-binding inhibitor of factor Xa. 814 99

Treatment of cultured bovine carotid artery endothelial cells with 10(-7) M plasmin increased arachidonate release coupled with the increase in prostacyclin production. The stimulatory effect of plasmin on arachidonate release could be divided into the early and late phases according to its calcium dependency and pertussis toxin sensitivity. The early phase of plasmin-induced arachidonate release was a calcium-dependent and pertussis toxin-sensitive response, which was observed within 20 min after plasmin treatment. The late phase was a calcium-independent and pertussis toxin-insensitive response, which was induced gradually from 20 to 60 min. Induction of the early phase of plasmin's effect required both the lysine binding and catalytic sites in plasmin molecule because it was inhibited either by the binding antagonist tranexamic acid or by the serine protease inhibitor aprotinin. Guanosine 5'-O-(2-thiotriphosphate) potentiated the effect of plasmin in permeabilized or nonpermeabilized cells, indicating that the early phase effect was mediated by a pertussis toxin-sensitive guanosine 5'-triphosphate (GTP)-binding protein. The late phase of plasmin's effect was due to the catalytic activity because it was inhibited by aprotinin but not by tranexamic acid. Microplasmin structurally having the catalytic sites induced a similar late phase effect. Plasmin did not elicit the metabolism of phosphatidyl polyphosphoinositides. These studies demonstrate that the activation of phospholipase A2, which results in arachidonate release, in the early phase of plasmin's effect is a receptor-mediation via GTP-binding protein that is not coupled through phospholipase C activation.
...
PMID:Human plasmin induces a receptor-mediated arachidonate release coupled with G proteins in endothelial cells. 838 26

Hereditary angioedema is caused by a genetic deficiency of C1-inhibitor, a serine protease inhibitor that regulates activation of complement, contact, and fibrinolytic systems. Symptoms (bouts of subcutaneous and mucous swelling) depend on the release of a vasoactive mediator, probably through activation of these three systems. We studied the interrelationship among complement, contact, and fibrinolytic activation in 23 patients with hereditary angiodema, 18 during remission and five during an attack, by measuring plasma levels of C1-C1 inhibitor, factor XIIa-C1 inhibitor, kallikrein-C1 inhibitor, and plasmin-alpha 2-antiplasmin complexes, tissue plasminogen activator, and urokinase plasminogen activator. In addition, cleavage of high-molecular weight kininogen was detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis and quantified by densitometry. During remission, plasma levels of C1-C1 inhibitor complexes were elevated (p = 0.0002), whereas the other parameters were within the normal range. During acute attacks, not only plasma levels of C1-C1 inhibitor complexes but also those of plasmin-alpha 2-antiplasmin complexes (P = 0.0009) and cleaved high-molecular weight kininogen were elevated. A positive correlation between plasmin-alpha 2-antiplasmin complexes and cleaved high-molecular weight kininogen was observed (r = 0.75, p < 0.001). This article presents the first in vivo evidence that supports the concept that release of vasoactive mediators in hereditary angiodema attacks is associated with the activation of the fibrinolytic system.
...
PMID:Generation of plasmin during acute attacks of hereditary angioedema. 842 80

Protease nexin 1 (PN1), a serine protease inhibitor that inactivates thrombin, urokinase, and plasmin, is produced abundantly in cultures of human fibroblasts and rat and human glioma cells. The major sites of PN1 synthesis in vivo and the specific physiological function(s) of this serpin are unknown. Using Northern blot analysis and a full-length PN1 cDNA probe we demonstrated the presence of PN1 mRNA in human term placentas. In situ hybridization of placental tissue with a PN1 riboprobe showed that PN1 mRNA is present throughout the placenta and is also abundant in the placental membranes. Immunohistochemical analysis with an anti-PN1 antibody showed co-localization of PN1 and its mRNA within the placenta.
...
PMID:Protease nexin 1 is expressed in the human placenta. 845 23


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---