Other Notes Review: Vitamin K and γ-carboxyglutamate biosynthesis1; Metabolic functions and mechanism of action2 Biochem/physiol Actions Vitamin K1 (Phylloquinone) is a lipid soluble polycyclic aromatic ketone used as a cofactor in the formation of coagulation factors II (prothrombin), VII, IX and X; anticoagulant factors protein C and S and as a cell signaling factor.