title: Isolation of the tissue factor inhibitor produced by HepG2 hepatoma cells.
abstract: Progressive inhibition of tissue factor activity occurs upon its addition to human plasma (serum). This process requires the presence of factor VII(a), facto-X(a), Ca2+, and another component in plasma that we have called the tissue factor inhibitor (TFI). A TFI secreted by HepG2 cells (human hepatoma cell line) was isolated from serum-free conditioned medium in a four-step procedure including CdCl2 precipitation, diisopropylphosphoryl-factor Xa affinity chromatography, Sephadex G-75 superfine gel filtration, and Mono Q ion-exchange chromatography. The purified TFI contained a predominant band at Mr 38,000 on NaDodSO4/polyacrylamide gel electrophoresis that comigrates with inhibitory activity. Like the activity present in plasma, this TFI requires the presence of factor VII(a), factor X(a), and Ca2+ to express inhibitory activity. Its specific activity (assuming an extinction coefficient of 10 at 280 nM, for a 1-cm path length through a 1% solution) was 9800 units/mg of protein, where 1 unit of TFI activity was defined as that present in 1 ml of normal pooled serum.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D002460:Cell Line; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D006801:Humans; D007202:Indicators and Reagents; D007700:Kinetics; D008074:Lipoproteins; D008113:Liver Neoplasms / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D000596:Amino Acids; D007202:Indicators and Reagents; D008074:Lipoproteins; D009363:Neoplasm Proteins; C051928:lipoprotein-associated coagulation inhibitor