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)

We report the production, purification, characterization, and partial amino acid sequence of a plasminogen inhibitor (PA-I). The starting material is culture fluid from phorbol myristate 13-acetate-treated U-937 cells and the isolation steps consist of preparative isoelectric focusing followed by affinity chromatography on Cibacron Blue-Sepharose. PA-I migrates as a closely spaced doublet of 47-kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and forms covalent complexes with urokinase and two-chain tissue-type plasminogen activator, displaying second order rate constants of 0.9 X 10(6) M-1 s-1 and 0.2 X 10(6) M-1 s-1, respectively. Upon treatment with 1 M NH4OH, the covalent complexes were hydrolyzed, yielding a 35-kDa inhibitor fragment. A partial amino acid sequence of PA-I showed that it belongs to the antithrombin III family of inhibitors. PA-I is immunologically related to a PA-inhibitor from human placenta. mRNA from phorbol myristate 13-acetate-treated U-937 cells directed, in a rabbit reticulocyte derived cell-free system, the biosynthesis of only one 47-kDa protein that could be immunoprecipitated with anti-PA-I IgG, indicating that the two molecular forms of PA-I are the products of post-translational processing.
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PMID:Purification and characterization of a plasminogen activator inhibitor from the histiocytic lymphoma cell line U-937. 309 45

Plasminogen activator-inhibitor complexes were analyzed by SDS-polyacrylamide gel electrophoresis and enzymography. The complexes appeared as fibrinolytically active bands in the fibrin-indicator gel. A high-molecular-weight t-PA form comigrating with a t-PA-inhibitor complex (Mr 95 000-135 000) from cultured human endothelial cells was purified from plasma by immunoadsorption on anti-t-PA-Sepharose followed by gel filtration on Sephadex G-150. The high-molecular-weight t-PA form was fibrinolytically inactive when assayed by the fibrin-plate method. It was converted to a form with the same electrophoretic mobility as t-PA (Mr 72 000) when treated with 1.5 M NH4OH/39 mM SDS. These observations suggested that the plasma high-molecular-weight t-PA form was an enzyme-inhibitor complex. The complex did not show immunological cross-reactivity with a number of known plasma serine proteinase inhibitors. Both t-PA and u-PA rapidly formed complexes with an inhibitor which was present in plasma in pmolar concentrations. p-Aminobenzamidine blocked the reaction, indicating that the active center of the activator was indeed implicated in complex formation. The complex between the plasma inhibitor and t-PA and the high-molecular-weight t-PA had the same electrophoretic mobilities. The rapid plasminogen activator inhibitor in plasma showed remarkable similarity to a plasminogen activator inhibitor from cultured human endothelial cells. In addition to the high-molecular-weight t-PA form described above, three other t-PA forms were isolated from plasma. Our results indicated that they represented free t-PA and t-PA in complex with respectively C1-esterase inhibitor and alpha 2-antiplasmin.
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PMID:Isolation of tissue-type plasminogen activator-inhibitor complexes from human plasma. Evidence for a rapid plasminogen activator inhibitor. 643 84

Serum-free conditioned media and cell extracts from cultured human umbilical vein endothelial cells were analyzed for plasminogen activator by SDS-polyacrylamide gel electrophoresis and enzymography on fibrin-indicator gels. Active bands of free and complexed tissue-type plasminogen activator (t-PA) or urokinase-type plasminogen activator (u-PA) were identified by the incorporation of specific antibodies against, respectively, t-PA or u-PA in the indicator gel. The endothelial cells predominantly released a high-molecular-weight t-PA (95 000-135 000). This t-PA form was converted to Mr-72 000 t-PA by 1.5 M NH4OH/39 mM SDS. A component with high affinity for both t-PA and u-PA could be demonstrated in serum-free conditioned medium and endothelial cell extract. The complex between this component and Mr-72 000 t-PA comigrated with high-molecular-weight t-PA. From the increase in Mr of t-PA or u-PA upon complex formation, the Mr of the endothelial cell component was estimated to be 50 000-70 000. The reaction between t-PA or u-PA and the plasminogen activator-binding component was blocked by 5 mM p-aminobenzamidine, while the complexes, once formed, could be cleaved by 1.5 M NH4OH/39 mM SDS. These observations indicated that the active center of plasminogen activator was involved in the complex formation. It was further noted that serum-free conditioned medium or endothelial cell extract inhibited plasminogen activator activity when assayed by the fibrin-plate method. Evidence is provided that the plasminogen activator-binding component was different from a number of the known plasma serine proteinase inhibitors, the placenta inhibitor and the fibroblast surface protein, proteinase-nexin. We conclude that cultured endothelial cells produce a rapid inhibitor of u-PA and t-PA as well as a t-PA-inhibitor complex.
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PMID:Human endothelial cells produce a plasminogen activator inhibitor and a tissue-type plasminogen activator-inhibitor complex. 643 88