Vitamin K-dependent coagulation factor (e.g., Prothrombin, Factor VII, Factor IX, Factor X), Protein C, Protein S (VKCF (Vitamin K-dependent coagulation factor), PC (Protein C), PS (Protein S))

Vitamin K-dependent coagulation factors are a group of plasma glycoproteins essential for the normal process of blood clot formation; they include prothrombin (factor II), factor VII, factor IX, and factor X (all acting as serine proteases in the coagulation cascade), along with the regulatory proteins C and S, which are natural anticoagulants. Activation and functional capacity of these proteins require a post-translational γ-carboxylation of glutamic acid residues, a process strictly dependent on vitamin K. Deficiencies (congenital or acquired) in these proteins result in either excessive bleeding (due to poor clot formation) or increased risk of thrombosis (particularly with protein C or protein S deficiency, leading to unopposed procoagulant activity). Clinical manipulation of this system is the foundation for oral anticoagulant therapy, which inhibits the vitamin K cycle[1][2][3][4][5][6][7][8][9].

Other names

Vitamin K-dependent clotting factorVKCFProtein C (PC)Protein S (PS)Prothrombin (Factor II)Factor VIIFactor IXFactor XVK-dependent anticoagulant proteinsVK-dependent factors

Inhibitors (e.g., warfarin) prevent γ-carboxylation of VKD proteins, lowering activity and reducing coagulation Vitamin K supplementation restores carboxylation and activity Protein C concentrates provide replacement in deficiency