Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A modification of the fibrin plate method is presented. Plasminogen-free human fibrinogen and plasminogen purified by affinity chromatography have been used. Fibrin plates without and with a constant amount of plasminogen and with agarose as stabilizing medium were used for the estimation of plasmin and plasminogen activator activity. Activator activity could be demonstrated in sterile bile and saliva. When plasmin activity was present, estimations of plasminogen activator were approximate. The method is sensitive, small volumes of reagents and samples are needed. The error of the method is comparatively low and the reproducibility is good.
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PMID:Fibrin plate method with reagents purified by affinity chromatography and its use for determination of fibrinolytic and other proteolytic activity in saliva, bile and plasma. 0 32

Psoriatic scale proteases were found to be extracted effectively in salt solution (1 mol/l) containing Triton X-100 (5 g/l). The extraction in dilute buffer or sucrose yielded low activities. The acid (0.25 N H2SO4) and KSCN (2 mol/l) solutions effectively extracted plasminogen activator. Fibrinolysin was most active in salt (1 mol/l KCl) and in KSCN (2 mol/l) extracts. Psoriatic scale proteases were fractionated by Sephadex G-100 gel filtration and further by DEAE cellulose chromatography. Five different enzyme preparations were obtained. The first preparation, resembling cathepsin D, effectively hydrolysed hemoglobin at pH 3.5 and casein at pH 5.8 and was insensitive to protease modifiers. The second preparation effectively hydrolysed trypsin substrates (AGLME, TAME, BAEE and BANA) and also histone and casein at pH 7.2 and was inhibited by protease inhibitors, TLCK and E-600. The third preparation hydrolysed histone and casein at pH 10.2 and was effectively inhibited by E-600 and partially by protease inhibitors and TPCK. The fourth preparation, resembling cathepsin B1, hydrolysed BANA and BAEE at pH 5.8 and was activated by SH-reagents and EDTA. The fifth enzyme preparation hydrolysed ATEE and was inhibited by E-600 and TPCK. Plasminogen activator was found mainly in the second enzyme preparation and fibrinolysin activity in the third and fifth enzyme preparations. The second, third and fifth enzyme preparations were different from the enzymes found in healthy human skin. The proteases of psoriatic scale resemble those of tissue and cell cultures undergoing rapid cell division. The possible role of proteases in the increased cell division in psoriasis plaque is discussed.
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PMID:Human skin proteases. Fractionation of psoriasis scale proteases and separation of a plasminogen activator and a histone hydrolysing protease. 0 31

Plasminogen activator production by cultured mouse peritoneal macrophages can be modulated in vitro by low concentrations of various pharmacologically active molecules. Glucocorticoid hormones and their synthetic derivatives, as well as cholera toxin, colchicine, and vinblastine markedly inhibit production of this enzyme without affecting other important macrophage functions. The effect of glucocorticoids is of particular interest, both because their relative in vivo anti-inflammatory potencies correlate exactly with their effect on plasminogen activator production in culture and because this effect occurs at near physiological concentrations. In view of the correlations established in other systems between plasminogen activator production and cell migration, we have also examined the age of the macrophages in thioglycollate-induced exudates. Confirming the results of Van Furth and Cohn (1968), we have found that the majority of these cells are young, having recently replicated and arrived in the peritoneal cavity. Using a fibrinagar overlay technique which allowed us to determine the production of plasminogen activator by individual cells. we have found that the majority of these cells produce the enzyme. The potential roles of plasminogen activator in monocyte migration and the relationship of this enzyme to the anti-inflammatory effect of gluccorticoids are correlated and emphasized.
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PMID:Macrophage plasminogen activator: modulation of enzyme production by anti-inflammatory steroids, mitotic inhibitors, and cyclic nucleotides. 6 Oct 67

Glucocorticoids rapidly and completely inhibit intracellular plasminogen activator activity in rat hepatoma cells, as assayed by the solubilization of 125I-labeled fibrin. Experiments in which extracts of dexamethasone-treated cells are mixed with extracts of control cells demonstrate an inhibitor of protease activity. Plasminogen activator is found primarily in the particulate fraction of cell lysates, whereas the inhibitor is localized in the soluble fraction. Variant cells have been isolated previously that are fully resistant to the dexamethoasone inhibition of plasminogen activator activity. These variants have no demonstrable inhibitor activity, whereas plasminogen activator in these cells is fully sensitive to inhibitor from wild-type cells. Thus, the basis for hormone resistance appears to be the failure of dexamethasone to induce an inhibitor.
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PMID:Mechanism of dexamethasone inhibition of plasminogen activator in rat hepatoma cells. 10

A procedure is presented for purifying a novel proteinase inhibitor in human plasma whose apparent unique biological property is to inhibit efficiently the lysis of fibrin clots induced by plasminogen activator. The final product is homogeneous as judged by disc gel electrophoresis, and immunoelectrophoresis. Its molecular weight estimated by sodium dodecyl sulfate gel electrophoresis or sedimentation equilibrium is 67,000 and 63,000, respectively. The inhibitor is a glycoprotein consisting polypeptide chain containing 11.7% carbohyrate. It migrates in the alpha2-globulin region in immunoelectrophoresis. The inhibitor is chemically and immunologically different from all the other known inhibitors in plasma. Inhibition of plasmin by the inhibitor is almost instantaneous even at 0 degrees, in contrast to the slow inhibition of urokinase (plasminogen activator in urine). Plasminogen activation by urokinase-induced clot lysis is inhibited by the inhibitor mainly through a mechanism of instantaneous inhibition of plasmin formed and not through the inhibition of urokinase. The inhibitor also inhibits trypsin. Consequently, it is suggested that this newly identified inhibitor is named alpha2-plasmin inhibitor or alpha2-proteinase inhibitor. A specific antibody directed against the inhibitor neutralizes virtually all inhibitory activity of plasma to activator-induced clot lysis. Immunochemical quantitation of the inhibitor was specific antiserum to the inhibitor and the purified inhibitor as a standard indicates that the concentration of the inhibitory in the serum of a healthy man is in or near the range of 5 to 7 mg/100 ml, which is the lowest concentration among the concentration of the proteinase inhibitors in plasma. The inhibitor and plasmin, trypsin, or urokinase form a complex which cannot be dissociated with denaturing and reducing agents. The formation of the enzyme-inhibitor complex occurs on a 1:1 molar basis and is associated with the cleavage of a unique peptide bone, which is most clearly demonstrated in the interaction of the inhibitor and beta-trypsin. In the complex formation between the inhibitor and plasmin, the inhibitor is cross-linked with the light chain which contains the active site of plasmin. It is suggested that, in a fashion analogous to complex formation between alpha1-antitrypsin and trypsin, the cross-links are formed between the active site serine of the enzyme and the newly formed COOH-terminal residue of the inhibitor, with cleavage of a peptide bond.
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PMID:Isolation and characterization of alpha2-plasmin inhibitor from human plasma. A novel proteinase inhibitor which inhibits activator-induced clot lysis. 13 98

Plasminogen, plasminogen activator, protease inhibitors, and a proteolytic activity are shown to be present in bovine follicular fluid. Much of the proteolytic activity appears to be due to plasmin. In addition, plasminogen activator activity can be demonstrated in follicle wall homogenates. Evidence that plasmin decreases the tensile strength of follicle wall preparations is also reported. The potential for the involvement of these substances in ovulation is discussed.
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PMID:Follicular plasminogen and plasminogen activator and the effect of plasmin on ovarian follicle wall. 15 88

Mouse teratocarcinoma cells from embryoid bodies were cultured in vitro to permit their differentiation into a number of cell types. Two enzyme activities, creatine phosphokinase (CPK) and the protease plasminogen activator, were studied to follow the developmental sequence of events in these embryoid body-derived cell cultures. CPK activity increased with time in culture, indicating the appearance of new cell types with brain- or muscle-specific enzyme activities. Plasminogen activator was detectable in extracts of embryoid bodies. This protease activity first increased and then decreased to a low level as the embryoid bodies in culture developed into differentiated cell types. These cell cultures also showed a decreased potential for tumor formation in syngeneic mice as a function of time in culture. This decrease in tumorigenic potential was correlated with the appearance of differentiated cells in vitro. Simian virus 40 (SV40) was used to infect and transform cells derived from embryoid bodies in culture. This was done to permit the establishment of cloned teratocarcinoma-derived cell lines. Twenty-nine distinct cloned permanent cell lines (called SVTER) containing the SV40-specific tumor antigen were obtained. None of these cell lines was capable of producing tumors in syngeneic mice. An analysis of the levels of creatine phosphokinase and plasminogen activator in these SVTER cell lines indicated that : (a) some cell lines had high CPK activity and little or no plasminogen activator activity, (b) some cell lines contained high levels of plasminogen activator activity with little or no CPK activity, and (c) some cell lines contained neither of these enzyme activities. No example of a cell line with high levels of both enzyme activities was observed, indicating that these two enzymes may participate in mutually exclusive developmental pathways. The SVTER cell lines may therefore be useful in reconstructing these developmental pathways in vitro.
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PMID:In vitro differentiation of teratomas and the distribution of creatine phosphokinase and plasminogen activator in teratocarcinoma-derived cells. 18 30

Plasminogen activator is produced by hamster cells transformed by human herpesviruses. These cell lines have previously been shown to be oncogenic when injected s.c. into newborn syngeneic hamsters. Lysis of fibrin overlays by these cell lines was plasminogen dependent. Normal hamster embryo fibroblasts and a hamster cell line transformed by PARA-7 (an adenovirus-SV 40 hybrid) failed to produced lysis. In separate experiments fibrin overlay of lytically infected secondary rabbit kidney cells did not show induction of this activity during the normal course of productive infection. The human cell line TE-85 clone F-5, a clonal cell line from a human osteogenic sarcoma, failed to produce plasminogen activator, but two separate clones of these cells that were morphologically transformed after exposure to UV-inactivated herpes simplex virus type 2 produced rapid lysis of the fibrin overlay. Clonal variation was observed in herpes simplex virus types 1 and 2-transformed hamster lines and is under investigation. It is suggested that plasminogen activator detection may serve as a convenient assay system for transformation of normal cells by herpesviruses.
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PMID:Production of plasminogen activator by cells transformed by herpesviruses. 20 45

Plasminogen activator was produced by both human embryo fibroblasts (a permissive system) and hamster embryo fibroblasts (a nonpermissive system) after exposure to human cytomegalovirus. The level of this activator was measured by using plates coated with [125I]fibrin. The production of plasminogen activator was enhanced when the human cells were exposed to human cytomegalovirus previously irradiated with UV light (5,520 to 55,200 ergs/mm2).
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PMID:Production of plasminogen activator by human and hamster cells infected with human cytomegalovirus. 22 62

During normal pregnancy, the concentrations of many of the clotting factors rise, thereby increasing the potential to generate fibrin. There is also evidence of increased thrombin activity during normal pregnancy which sharply increases during placental separation. Antithrombin III, the main inhibitor of thrombin and activated factor X, shows no compensatory rise during pregnancy but increases during the puerperium. Plasminogen and antiplasmin concentrations rise during pregnancy but systemic fibrinolytic activity, as measured by the euglobulin lysis time, is markedly depressed during pregnancy; the reduced fibrinolytic activity returns to non-pregnant values very soon after delivery. The loss of fibrinolytic activity is presumed to be loss of plasminogen activator, because when this is added in excess in the urokinase sensitivity test, the fibrinolytic response is normal. The capacity for localized fibrinolytic activity is not lost, however, because fibrinolytic degradation products are slightly raised during pregnancy. The overall pattern is one of increased coagulant and reduced fibrinolytic capacity during pregnancy which may protect the pregnant woman against the haemostatic challenge of placental separation.
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PMID:Blood clotting and fibrinolysis in pregnancy. 38 69


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