factor x factor x factor x, also known by the eponym stuart–prower factor, is an enzyme (ec 3.4.21.6) of the coagulation cascade. it is a serine endopeptidase (protease group s1, pa clan). factor x is synthesized in the liver and requires vitamin k for its synthesis. not to be confused with factor x (hemin) found in chocolate agar. f10available structurespdbortholog search: pdbe rcsb list of pdb id codes1c5m, 1ezq, 1f0r, 1f0s, 1fax, 1fjs, 1g2l, 1g2m, 1hcg, 1ioe, 1iqe, 1iqf, 1iqg, 1iqh, 1iqi, 1iqj, 1iqk, 1iql, 1iqm, 1iqn, 1ksn, 1lpg, 1lpk, 1lpz, 1lqd, 1mq5, 1mq6, 1nfu, 1nfw, 1nfx, 1nfy, 1p0s, 1v3x, 1wu1, 1xka, 1xkb, 1z6e, 2bmg, 2boh, 2bok, 2bq6, 2bq7, 2bqw, 2cji, 2d1j, 2ei6, 2ei7, 2ei8, 2fzz, 2g00, 2gd4, 2h9e, 2j2u, 2j34, 2j38, 2j4i, 2j94, 2j95, 2jkh, 2p16, 2p3f, 2p3t, 2p3u, 2p93, 2p94, 2p95, 2phb, 2pr3, 2q1j, 2ra0, 2uwl, 2uwo, 2uwp, 2vh0, 2vh6, 2vvc, 2vvu, 2vvv, 2vwl, 2vwm, 2vwn, 2vwo, 2w26, 2w3i, 2w3k, 2wyg, 2wyj, 2xbv, 2xbw, 2xbx, 2xby, 2xc0, 2xc4, 2xc5, 2y5f, 2y5g, 2y5h, 2y7x, 2y7z, 2y80, 2y81, 2y82, 3cen, 3cs7, 3ens, 3ffg, 3hpt, 3iit, 3k9x, 3kl6, 3q3k, 3sw2, 3tk5, 3tk6, 4a7i, 3kqb, 3kqc, 3kqd, 3kqe, 3liw, 3m36, 3m37, 4bti, 4btt, 4btu, 4y6d, 4y71, 4y76, 4y79, 4y7a, 4y7b, 4zha, 4zh8, 5k0hidentifiersaliasesf10, fx, fxa, coagulation factor xexternal idsomim: 613872 mgi: 103107 homologene: 30976 genecards: f10 gene location (human)chr.chromosome 13 (human)band13q34start113,122,799 bpend113,149,529 bpgene location (mouse)chr.chromosome 8 (mouse)band8 a1.1|8 5.73 cmstart13,087,308 bpend13,106,676 bprna expression patternbgeehumanmouse (ortholog)top expressed inright lobe of liverstromal cell of endometriumcanal of the cervixgastric mucosaright coronary arteryleft uterine tubeislet of langerhansright lungleft coronary arterygallbladdertop expressed inleft lobe of liveryolk sacgallbladderbloodsexually immature organismbone marrowprimitive streakright lung lobeabdominal wallileummore reference expression databiogpsmore reference expression datagene ontologymolecular function calcium ion binding peptidase activity protein binding serine-type peptidase activity serine-type endopeptidase activity phospholipid binding hydrolase activity cellular component endoplasmic reticulum lumen intrinsic component of external side of plasma membrane plasma membrane extracellular region golgi lumen extracellular space biological process hemostasis positive regulation of protein kinase b signaling positive regulation of cell migration blood coagulation proteolysis endoplasmic reticulum to golgi vesicle-mediated transport blood coagulation, extrinsic pathway sources:amigo / quickgoorthologsspecieshumanmouseentrez215914058ensemblensg00000126218ensmusg00000031444uniprotp00742o88947refseq (mrna)nm_000504nm_001312674nm_001312675nm_001242368nm_007972refseq (protein)np_000495np_001299603np_001299604np_001229297np_031998location (ucsc)chr 13: 113.12 – 113.15 mbchr 8: 13.09 – 13.11 mbpubmed searchwikidataview/edit humanview/edit mouse factor x is activated, by hydrolysis, into factor xa by both factor ix (with its cofactor, factor viii in a complex known as intrinsic tenase) and factor vii with its cofactor, tissue factor (a complex known as extrinsic tenase). it is therefore the first member of the final common pathway or thrombin pathway. it acts by cleaving prothrombin in two places (an arg-thr and then an arg-ile bond), which yields the active thrombin. this process is optimized when factor xa is complexed with activated co-factor v in the prothrombinase complex. factor xa is inactivated by protein z-dependent protease inhibitor (zpi), a serine protease inhibitor (serpin). the affinity of this protein for factor xa is increased 1000-fold by the presence of protein z, while it does not require protein z for inactivation of factor xi. defects in protein z lead to increased factor xa activity and a propensity for thrombosis. the half life of factor x is 40–45 hours. structure