Which blood-clotting factors require vitamin K for their synthesis?

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Several translucent, oval-shaped vitamin E gel capsules are scattered on a white surface near a partially visible bottle. — vitamin Vitamin E in gel-cap form.

Vitamin K is essential for the complete synthesis of six specific proteins involved in the process of blood coagulation. These proteins are synthesized in the liver in a precursor form and require vitamin K as a cofactor for an enzyme-mediated reaction known as γ-carboxylation.1

The six proteins that require vitamin K for their synthesis are:

Factor II (prothrombin)
Factor VII
Factor IX
Factor X
Protein C
Protein S

During γ-carboxylation, specific glutamic acid residues are modified into γ-carboxyglutamic acid, which allows these proteins to bind to calcium and interact with cell membranes. Without vitamin K, these proteins remain biologically inactive, leading to impaired blood clotting.12