title: Allosteric activation of coagulation factor VIIa.
abstract: Coagulation factor VIIa (FVIIa) is present at subnanomolar concentration and represents a small percentage of the total amount of FVII in the circulation. FVIIa is poised to initiate blood clotting when it encounters its pivotal cofactor tissue factor (TF) which becomes exposed to blood upon vascular rupture. The requirement for complex formation with TF in order for FVIIa to express procoagulant activity ensures thrombin and fibrin generation at the right time and place. Thus TF acts as a guardian of safety of paramount importance to blood coagulation by providing localization to the site of injury and at the same time inducing maturation of zymogen-like free FVIIa to the active cofactor-bound enzyme. This review gives an account of the accumulated knowledge about the structure, function and TF dependence of FVIIa to arrive at a plausible allosteric mechanism by which TF induces maturation of the active conformation of FVIIa.
authors.affiliation: Haemostasis Biochemistry, Novo Nordisk A/S, Novo Nordisk Park, DK-2760 Maaloev, Denmark. egpe@novonordisk.com
authors.forename: Egon
authors.initials: E
authors.lastname: Persson
authors.forename: Ole Hvilsted
authors.initials: OH
authors.lastname: Olsen
mesh_terms: D000494:Allosteric Regulation; D000818:Animals; D001777:Blood Coagulation / Q000502:physiology; D015942:Factor VIIa / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D013925:Thromboplastin / Q000737:chemistry / Q000378:metabolism
chemical_list: D046912:Multiprotein Complexes; D013925:Thromboplastin; D015942:Factor VIIa