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)

The negative surface charge of human granulocytes was diminished after incubation with the chemotactic factors C5a, dialyzable transfer factor, and the enzymes kallikrein and plasminogen activator. No such change was observed after incubation with human IgG, albumin, horeseradish peroxidase, or a mixture of prekallikrein and plaminogen proactivator. Hydrocortisone inhibited the effect of C5a upon granulocyte surface charge and inhibited its chemotactic activity, suggesting that steroids act at the cell surface. The chemotactic inhibitors cholchicine and cytochalsin B had no effect upon granulocyte surface charge, consistent with their presumed effect upon microtubules and microfilaments, respectively. The data suggest that the decrease in cell surface charge may be a preerequiste for normal cell movement.
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PMID:Interaction of leukocyte chemotactic factors with the cell surface. I. Chemotactic factor-induced changes in human granulocyte surface charge. 112 32

An enzyme-linked immunosorbent assay (ELISA) for quantitation of natural and recombinant plasminogen activators containing the serine protease domain (B-chain) of urokinase-type plasminogen activator (u-PA) was developed, based on two murine monoclonal antibodies, MA-4D1E8 and MA-2L3, raised against u-PA and reacting with non-overlapping epitopes in the B-chain. MA-4D1E8 was coated on microtiter plates and bound antigen was quantitated with MA-2L3 conjugated with horseradish peroxidase. The intra-assay, inter-assay and inter-dilution coefficients of variation of the assay were 6%, 15% and 9%, respectively. Using recombinant single-chain u-PA (rscu-PA) as a standard, the u-PA-related antigen level in normal human plasma was 1.4 +/- 0.6 ng/ml (mean +/- SD, n = 27). The ELISA recognized the following compounds with comparable sensitivity: intact scu-PA (amino acids, AA, 1 to 411), scu-PA-32k (AA 144 to 411), a truncated (thrombin-derived) scu-PA comprising AA 157 to 411, and chimeric t-PA/u-PA molecules including t-PA(AA1-263)/scu-PA(AA144-411), t-PA(AA1-274)/scu-PA(AA138-411) and t-PA(AA87-274)/scu-PA(AA138-411). Conversion of single-chain to two-chain forms of u-PA or inhibition of active two-chain forms with plasminogen activator inhibitor-1 or with the active site serine inhibitor phenyl-methyl-sulfonyl fluoride, did not alter the reactivity in the assay. In contrast, inactivation with alpha 2-antiplasmin or with the active site histidine inhibitor Glu-Gly-Arg-CH2Cl resulted in a 3- to 5-fold reduction of the reactivity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:An enzyme-linked immunosorbent assay for urokinase-type plasminogen activator (u-PA) and mutants and chimeras containing the serine protease domain of u-PA. 137 17

A technically easy and sensitive method for the evaluation of the fibrinolytic potency of plasminogen activator in a circulating plasma system was developed. A circulating apparatus was prepared by connecting silicone tubes with two separate chambers. Human plasma and plasminogen activator were allowed to circulate from one chamber through a peristaltic pump into another one which contained biotin-labeled fibrin clot. The extent of fibrinolysis was evaluated on streptavidin-coated microtiter plates by measuring the amount of the avidin-bound fibrin degradation products with peroxidase-linked antibody. The detection limit of the fibrinolytic products was 1.5 ng/ml. The present method dose not require any specialized equipment and is also applicable to a low-cost routine measurement of the thrombus selectivity of plasminogen activator.
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PMID:An enzyme-linked immunosorbent assay for the detection of plasminogen activator-induced fribrin clot lysis in a circulating plasma system. 160 54

A reproducible and sensitive one-step enzyme immunoassay (EIA) was developed to determine total tissue-type plasminogen activator (t-PA) antigen in plasma. The EIA comprises two monoclonal catching antibodies and a polyclonal (goat) tagging antibody conjugated with horseradish peroxidase. There is an equal reactivity towards the several physiological t-PA forms, i.e., single-chain t-PA, two-chain t-PA and t-PA in complex with its naturally occurring inhibitor plasminogen activator inhibitor-type 1 (t-PA/PAI-1 complex). Additionally, the EIA does not discriminate between human melanoma t-PA and recombinant t-PA (Activase). The assay has a lower detection limit of approximately 0.5 ng t-PA per ml plasma, with a time-to-result of only 3.5 h.
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PMID:A one-step enzyme immunoassay for the determination of total tissue-type plasminogen activator (t-PA) antigen in plasma. 164 8

Oophorectomy was found to decrease the plasminogen activator activity of rat mammary tumors induced by 7,12-dimethylbenz(a)anthracene (DMBA) to less than 7 per cent, while in vivo estradiol treatment restored its activity in a dose dependent fashion. The peroxidase activity was not changed either by oophorectomy or by the administration of estrogen. In the rat uterus, plasminogen activator activity was not changed by oophorectomy or by the administration of estrogen, however, its peroxidase activity decreased to less than 2 per cent following oophorectomy, while estrogen administration restored its activity. Estrogen regulated plasminogen activator activity in the DMBA-induced rat mammary tumors but not in the uterus and thus, the specific hormonal regulation of this enzyme may be an important factor for the hormonal dependent growth of such tumors.
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PMID:Hormonal regulation of plasminogen activator and peroxidase activities in 7,12-dimethylbenz(a)anthracene-induced rat mammary tumors and the rat uterus. 164 4

The authors suggest a method for enzymic fibrinolytic activity measurements, based on the detection in the solution of degradation products of fibrin, prelabeled with peroxidase. The method is highly sensitive, permits the detection in solution of as little as 0.01 MU per ml of plasminogen activator. As the basic method, it can be employed for measurements of plasminogen activator, plasminogen activator inhibitors, and plasmin inhibitors in biologic fluids, blood plasma including. Since the method is simple and the majority of its steps may be automated, it can be used in clinical laboratories.
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PMID:[Determination of the enzyme activity of the fibrinolytic system using fibrinogen conjugated with peroxidase]. 172 43

Plasminogen activator (PA) was located in newborn rat osteoclasts using a single-cell assay. Immunohistochemistry using biotin-streptavidin-peroxidase indicated the presence of both tissue-type plasminogen activator (tPA) and urokinase (uPA) within the cytoplasm of osteoclasts isolated from newborn rat long bones. Electron microscopic immunohistochemistry using the biotin-streptavidin-colloidal gold system on L.R. Gold thin resin sections of undecalcified, newborn rat tibial metaphyseal trabecular bone identified these proteases in the lysosomal network of osteoclasts. uPA was also localized in marrow macrophage lysosomes, but tPA was not detected in these cells. The localization of these enzymes within osteoclasts may imply their involvement in bone resorption.
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PMID:Identification of plasminogen activator in osteoclasts. 211 31

Little is known about the functions of alveolar macrophages during the later resolving phases of pulmonary inflammation. We have used an animal model of resolving pulmonary inflammation to obtain inflammatory macrophages (IMs) and have compared several IM functions with those of resident macrophages (RMs). IMs were frequently peroxidase positive and contained large amounts of myeloperoxidase activity. IMs also contained significant amounts of a serine protease type of elastase. The procoagulant activity of IMs was less than that of RMs, and IMs exhibited increased plasminogen activator activity when incubated on fibrin matrices. IMs also degraded fibrin directly, without plasminogen, and this activity was due to two different enzymes of molecular weights 39 and 63 kD that were present in IM granules and plasma membranes. These results suggest that, in vivo, IMs take up PMN enzymes and alter their procoagulant and fibrinolytic activity to maximize fibrin removal. These IM functions may be important for successful resolution of inflammatory injury.
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PMID:Characteristics of alveolar macrophages in an animal model of resolving pulmonary inflammation. 216 24

Four monoclonal antibodies, MA-7D4, MA-7F5, MA-12A4 and MA-15H12, were raised against human plasminogen activator inhibitor-1 (PAI-1). MA-7D4 and MA-7F5 had an inhibitory effect on PAI-1 activity, whereas MA-15H12 and MA-12A4 did not affect PAI-1 activity. MA-7D4 was used previously as capture antibody in combination with MA-7F5 conjugated to horseradish peroxidase (7F5-HRP) to construct an ELISA which was 12 times more sensitive towards free PAI-1 as compared to PAI-1 in complex with human tissue-type plasminogen activator (t-PA) (Blood 71: 220-225, 1988). MA-15H12, as capture antibody, in combination with MA-12A4 corjugated to horseradish peroxidase (12A4-HRP) yielded an ELISA which was equally sensitive towards free PAI-1 and PAI-1/t-PA complex. Another ELISA was constructed using MA-15H12 as capture antibody in combination with an anti-t-PA antibody (MA-62E8) conjugated to horseradish peroxidase (62E8-HRP), allowing the specific measurement of t-PA/PAI-1 complexes and the development of an immunofunctional method for the specific quantitation of active PAI-1. These assays were then used to measure PAI-1 levels in plasma and the values obtained were compared with the data obtained by functional methods. It was found that 44% to 60% of free PAI-1 antigen in normal plasma is active and that t-PA occurs mainly as t-PA/PAI-1 complexes. In plasma from 48 patients suffering from angina pectoris no statistical difference in PAI-1 activity, PAI-1 antigen or PAI-1/t-PA complex could be observed as compared to normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Measurement of plasminogen activator inhibitor 1 (PAI-1) in plasma with various monoclonal antibody-based enzyme-linked immunosorbent assays. 231 99

Increasing evidence suggests the involvement of leukocytes in the fibrinolytic system. Monocytes secrete pro-urokinase (Grau, Thromb Res 1989; 53: 145) and it has been shown that these cells have specific receptors for urokinase and plasminogen (Miles, Thromb Haemostas 1987; 58: 936). The aim of this study was to analyse the presence of plasminogen activator inhibitor(s) in platelet-free suspensions of human peripheral blood monocytes and polymorphonuclear leukocytes (PMN). SDS-PAGE and reverse fibrin autography showed an inhibitory band of 50 kDa in the monocyte extracts (Triton X-100) but not in the PMN extracts. Urokinase (u-PA) was mixed with increasing amounts of monocyte extract for 10 min and the mixtures were added to 125I-fibrin coated wells containing plasminogen. A dose-dependent decrease in the u-PA fibrinolytic activity was observed. The amount of inhibition increased when the monocyte releasates were preincubated with u-PA (40% inhibition after 5 min preincubation and 80% after 15 min), indicating a direct interaction between this activator and an inhibitor(s). After SDS-PAGE of monocyte extracts, immunoblotting and peroxidase staining identified both PAI1 and PAI2, with an apparent molecular weight of 47-50 kDa. Monocyte-associated PAI1 formed complexes with single chain t-PA with a molecular mass 50 kDa higher than the molecular mass of the free PAI1. However, a significant amount of PAI1 remained unbound to t-PA. This inactive PAI1 could have come from a rapid inactivation of the primary active PAI1. These PAI1 and PAI2 detected in human monocytes may be transcendent in the regulation of the fibrinolytic system.
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PMID:Detection of both type 1 and type 2 plasminogen activator inhibitors in human monocytes. 233 62


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