A glycoprotein, synthesized in the liver, containing 10 Gla residues that are dependent on vitamin K for biosynthesis. It is the zymogen for the serine protease, Thrombin, and participates in the common pathway of coagulation. Conversion of Prothrombin to Thrombin is catalyzed by FXa in the presence of the cofactor FVa, calcium ions, and phospholipid (prothrombinase complex). The slide Coagulation Pathways (All Components) shows how FII relates to the other coagulation factors. See also the slide shows entitled Tissue Factor Pathway (Extrinsic) with Common Pathway (PT) and Intrinsic Pathway-APTT.
