Central regulator of hemostasis. It serves as a critical cofactor for the prothrombinase activity of factor Xa that results in the activation of prothrombin to thrombin.
Factor V deficiency Thrombophilia due to activated protein C resistance Budd-Chiari syndrome Ischemic stroke Pregnancy loss, recurrent, 1
Belongs to the multicopper oxidase family. Contains 3 F5/8 type A domains. Contains 2 F5/8 type C domains. Contains 6 plastocyanin-like domains.
Domain B contains 35 x 9 AA tandem repeats, and 2 x 17 AA repeats.
Thrombin activates factor V proteolytically to the active cofactor, factor Va (formation of a heavy chain at the N-terminus and a light chain at the C-terminus). Sulfation is required for efficient thrombin cleavage and activation and for full procoagulant activity. Activated protein C inactivates factor V and factor Va by proteolytic degradation. Phosphorylation sites are present in the extracellular medium.