– F10, also known as Coagulation factor X, belongs to the peptidase S1 family that is synthesized as a 488 amino acid (aa) with a signal peptide and a pro region (residues 1‑40). Both the intrinsic and extrinsic pathways activate Factor X to Xa, which consists of light (residues 41‑179) and heavy (residues 235‑488) chains linked by a disulfide bond. Coagulation factor X is initially synthesized in the liver. The two chains are formed from a single-chain precursor by the excision of two Arg residues and are held together by 1 or more disulfide bonds. Forms a heterodimer with SERPINA5. F10 is a vitamin K-dependent glycoprotein that converts prothrombin to thrombin in the presence of factor Va, calcium and phospholipid during blood clotting.