Vitamin K–dependent clotting factor (null)

“Vitamin K–dependent clotting factor” is a collective, not singular, term describing a group of plasma proteins essential for the normal clotting (coagulation) process in blood. These proteins require post-translational gamma-carboxylation of specific glutamic acid (Glu) residues, a reaction that depends on vitamin K as a cofactor, to acquire calcium-binding capability and full biological activity. The classical vitamin K–dependent clotting factors are **Factor II (prothrombin)**, **Factor VII**, **Factor IX**, and **Factor X**. Additionally, **protein C**, **protein S**, and *protein Z* are vitamin K–dependent proteins with regulatory (anticoagulant) or other roles. These proteins play key roles in the coagulation cascade: procoagulant factors initiate and propagate clot formation, while anticoagulant proteins regulate or prevent excessive clotting. Deficiency or pharmacological inhibition (e.g., with warfarin) of vitamin K leads to undercarboxylation, dysfunctional clotting factors, and increased bleeding risk. Monitoring is done via PT/INR assays and/or individual factor assays. The term “Vitamin K–dependent clotting factor” itself is not a unique molecular entity but a functional group, and should be further specified (e.g., “Prothrombin (Factor II)”) when describing a therapeutic or biochemical target[1][3][4][5][6][7][9]. **Important note:** As written, “Vitamin K dependent clotting factors” is collective and does not refer to one unique molecule, but several proteins (most importantly Factors II, VII, IX, X, and also protein C, S, and Z). For research and database purposes, it is strongly recommended to specify the exact factor if possible. **is_incorrect:** true, as this term is non-specific for a molecular target.

Other names

Vitamin K–dependent coagulation factorVKD clotting factorVitamin K–dependent plasma protein

Inhibitors (e.g., warfarin) block vitamin K epoxide reductase, preventing gamma-carboxylation, thus reducing activation of these clotting factors[6][1][4] Supplementation of vitamin K restores gamma-carboxylation and function