Factor Xa is a vitamin K-dependent glycoprotein that converts prothrombin to thrombin in the presence of factor Va, calcium and phospholipid during blood clotting. Selective cleavage of Arg-|-Thr and then Arg-|-Ile bonds in prothrombin to form thrombin. Inhibited by SERPINA5 and SERPINA10. 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. Plasma; synthesized in the liver. The vitamin K-dependent, enzymatic carboxylation of some glutamate residues allows the modified protein to bind calcium. N- and O-glycosylated. O-glycosylated with core 1 or possibly core 8 glycans. Proteolytically cleaved and activated by cathepsin CTSG (PubMed:8920993). The activation peptide is cleaved by factor IXa (in the intrinsic pathway), or by factor VIIa (in the extrinsic pathway) (By similarity). The iron and 2-oxoglutarate dependent 3-hydroxylation of aspartate and asparagine is (R) stereospecific within EGF domains. The disease is caused by variants affecting the gene represented in this entry. Belongs to the peptidase S1 family. Factor X entry