Identification and characterization of two thrombin-activatable fibrinolysis inhibitor isoforms.

摘要: Thrombin-activatable fibrinolysis inhibitor (TAFI) is synthesized by the liver and thought to circulate in plasma as a plasminogen-bound zymogen. When it activated thrombin/thrombomodulin complex, TAFI exhibits carboxypeptidase B-like activity. To study structure-function relationship of TAFI, we expressed recombinant human insect cells. During cloning cDNA from several libraries, identified second which differed published sequence at 2 positions. One these sequences resulted substitution alanine for threonine residue 147, other was silent mutation. These substitutions were found libraries different sources. Using Southern blot analysis, confirmed existence this polymorphism population. In order compare activation activity isoforms, both isoforms baculovirus expression system, compared enzyme kinetics purified proteins. The molecular weight lower than due differences glycosylation. two had similar enzymes towards small molecule substrates. Their ability retard clot lysis be plate assay.