Factor V, also known as coagulation factor V or labile factor, is a protein that plays a crucial role in the clotting process of blood. It is a glycoprotein, synthesized in the liver, and circulates in the plasma as an inactive precursor known as factor V. This precursor undergoes activation by thrombin, an enzyme involved in the clotting cascade.
Activated factor V, known as factor Va, acts as a cofactor for activated factor X, accelerating the rate at which prothrombin is converted to thrombin. Thrombin then converts fibrinogen into fibrin, which forms a mesh that traps blood cells and platelets, forming a clot to stop bleeding.
Factor V is inherited in an autosomal dominant pattern, which means a mutation in one copy of the gene is enough to cause a blood clotting disorder called factor V Leiden. This mutation leads to an increased risk of blood clots, as it renders factor V resistant to degradation, resulting in excessive clotting.
Clinical testing of factor V activity is performed through laboratory assays, which evaluate the ability of factor V to promote clotting. These tests are often used in the diagnosis and management of bleeding disorders and to monitor patients on anticoagulant therapy.
Overall, factor V plays a critical role in the coagulation pathway, enhancing the efficiency of thrombin-mediated blood clotting, and any dysfunctions in this protein can lead to abnormal clotting tendencies or bleeding disorders.
