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The activation of factor VII by a variety of potential activators
Author(s) -
KE KE,
Morrissey James
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.995.6
Subject(s) - factor ixa , chemistry , serine protease , thrombin , biochemistry , protease , plasmin , cofactor , factor vii , zymogen , proteolysis , factor x , prothrombinase , tissue factor , enzyme , coagulation , platelet , psychology , psychiatry , immunology , biology
Factor VII (VII) is an inactive zymogen, which upon proteolysis of a single peptide bond, is activated to the serine‐protease form factor VIIa (VIIa). It is known that in vitro factor Xa (Xa), factor IXa (IXa), thrombin, factor XIIa (XIIa), VIIa, and plasmin can activate VII to VIIa. In the present study, the activation of VII by potential in vivo activators was evaluated under identical conditions, in the absence and presence of cofactors. In order to avoid the influence of VIIa autoactivation to the analysis of VII activation by other activators, VII mutant (Sc195A) was generated, in which the active site serine residue has been mutated to alanine. Experiments were performed on phospholipid vesicles either in the presence of relipidated membrane‐TF, soluble TF, or none. The results show that among Xa, IXa, VIIa‐TF, meizothrombin, thrombin and XIIa, Xa and IXa are the most potent activators of VII. TF facilitates VII activation by 3 to 9‐fold, various from different activators. The cofactors for protease Xa and IXa do not influence the activation of VII. Preliminary data also shows that IXaα is one of the potent activators of VII. This study shed light on how VII get activated in physiological conditions.