Vitamin K-dependent coagulation factors (Factors II, VII, IX, X) (VKD factors)

The human coagulation factors II (prothrombin), VII, IX, and X are a group of serine proteases synthesized in the liver that are essential for the blood coagulation cascade [10, 16]. These factors are characterized by their requirement for vitamin K as a cofactor for the post-translational gamma-carboxylation of glutamic acid residues, a modification that allows them to bind calcium and assemble on phospholipid membranes to generate thrombin [1, 7]. In clinical medicine, these factors are the primary targets of vitamin K antagonists like warfarin, which are used to prevent and treat thromboembolic conditions such as atrial fibrillation and deep vein thrombosis [4, 9]. Conversely, prothrombin complex concentrates (PCC) containing these four factors are utilized as a rapid replacement therapy to manage life-threatening bleeding or to urgently reverse the effects of anticoagulants [2, 12]. Deficiencies in these factors, whether inherited (e.g., Hemophilia B for factor IX) or acquired (e.g., due to liver disease or vitamin K deficiency), result in significant bleeding diatheses [8, 21].

Other names

Human coagulation factors II, VII, IX, XProthrombin complexVitamin K-dependent clotting factorsFactors II, VII, IX, and X

Vitamin K antagonists (VKAs) inhibit the enzyme vitamin K epoxide reductase (VKORC1), which prevents the gamma-carboxylation of glutamic acid residues on factors II, VII, IX, and X, rendering them unable to bind calcium and phospholipids and thus procoagulant-inactive [2, 9]. Prothrombin complex concentrates (PCC) provide exogenous replacement of these factors to rapidly restore hemostasis in cases of severe bleeding or anticoagulant reversal [12, 15].