Coagulation Factor Xa

Participation of Factor Xa in Prothrombinase
The participation of the serine protease factor Xa in the prothrombinase complex is illustrated. Membrane bound factor Xa binds to membrane bound factor Va to form the prothrombinase complex. This complex effectively converts the zymogen prothrombin (II) to the active serine protease thrombin (IIa) by proteolytic removal of the fragment 1.2 (F1.2) portion of prothrombin.

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  • Mouse Factor Xa



    SKU: MCXA-5060 Category:
    Size 50 µg
    Formulation 50% glycerol/water (v/v)
    Storage -20°C
    Shelf Life 12 months
    Purity >95% by SDS-PAGE
    Activity Determination Factor X clotting assay or chromogenic assay
  • Rat Factor Ixa



    SKU: RATIXA-9050 Category:
    Size 50 µg, 1 mg
    Formulation 50% glycerol/water (v/v)
    Storage -20°C
    Shelf Life 12 months
    Purity >95% by SDS-PAGE
    Activity Determination Clotting assay

Activation of the zymogen, factor X, by either the intrinsic or extrinsic factor Xase complexes produces the active serine protease factor Xa (1,2). The activation of factor X requires proteolytic cleavage of the heavy chain, resulting in the release of an activation glycopeptide. The heavy chain region in factor Xa contains the serine protease catalytic domain, while the light chain, as in the zymogen, contains the membrane binding domain.

Factor Xa (molecular weight 46,000) participates in the prothrombinase complex, which catalyzes the rapid conversion of prothrombin to thrombin. Prothrombinase is an enzyme complex composed of factor Xa (enzyme) and factor Va (cofactor) assembled on a cellular surface in the presence of calcium ions. Although factor Xa can independently catalyze the activation of prothrombin, the rate at which this reaction occurs is increased nearly 300,000-fold with complete assembly of the prothrombinase complex. The clotting activity of factor Xa in vivo is terminated by either inactivation of the cofactor, factor Va, or by direct inhibition of factor Xa by inhibitors, such as ATIII, after disassembly of the prothrombinase complex.

In addition to its broad application in coagulation research, factor Xa can be utilized for site specific cleavage of fusion proteins expressed in bacteria (9-12). A factor Xa-sensitive site is incorporated between the recombinant protein of interest and peptides or proteins which facilitate purification and/or expression. The target protein is released from the expressed hybrid by cleavage with factor Xa. The factor Xa can then be easily removed by affinity chromatography.

Factor Xa is prepared by activating purified factor X with the factor X activator isolated from Russell’s viper venom. Factor Xa is purified from the activation mixture by chromatography over benzamidine-Sepharose followed by gel filtration (1,3). Several modified forms of factor Xa are also available including: A) active-site blocked factor Xa containing either the tripeptide chloromethyl ketone inhibitor EGRck, or the fluorescent inhibitor Dansyl-EGRck; and B) human Gla-domainless β-factor Xa. The enzyme is supplied in 50% (vol/vol) glycerol/H2O and should be stored at -20°C. Purity is determined by SDS-PAGE analysis and activity is measured in a factor Xa clotting assay and/or chromogenic substrate assay.  Lot to lot consistency ensures reproducible results every time.

Cell culture: For experiments involving cell cultures, please contact us to discuss custom, low endotoxin lots designated for cell culture use.

Sample gel image
GelNovex 4-12% Bis-Tris
LoadHuman Factor Xa, 1 µg per lane
StandardSeeBluePlus 2; Myosin (191 kDa), Phosphorylase B (97 kDa), BSA (64 kDa), Glutamic Dehydrogenase (51 kDa), Alcohol Dehydrogenase (39 kDa), Carbonic Anhydrase (28 kDa), Myoglobin Red (19 kDa), Lysozyme (14 kDa)
Special NotesHeavy chain is a doublet due to the presence of up to 50% beta form. The conversion of alpha-Xa to beta-Xa occurs by autocleavage of alpha-Xa by alpha-Xa resulting in the loss of a COOH-terminal peptide.
Mode of actionEnzyme component of the prothrombinase complex
Molecular weight46,000 (human) (4)
45,300 (bovine) (5)
Extinction coefficient
1 %
1 c m, 280 nm
= 11.6 (human) (9)
  = 12.4 (bovine) (7)
Specific Activityapproximately 1000 units/mg
Structuretwo subunits, Mr=16,200 and 29,000 (human) (6), Mr=16,500 and 28,800 (bovine) (5), NH2-terminal gla domain, two EGF domains
Percent carbohydrate3.0 % (human) (8)
2.1 % (bovine) (8)
Post-translational modificationseleven gla residues,
one β-hydroxyaspartate
  1. Jesty, J., et al., Methods Enzymol., 45, 95 (1976).
  2. Jackson, C.M., Ann. Rev. Biochem., 49, 765 (1980).
  3. Krishnaswamy, S., et al., J.Biol. Chem., 262, 3291 (1987).
  4. Discipio, R.G., et al., Biochemistry, 16, 5253 (1977).
  5. Fujikawa, K. and Davie, E.W., Methods Enzymol., 45, 89 (1976).
  6. Krishnaswamy, S., et al., J. Biol. Chem., 261, 8997 (1986).
  7. Discipio, R.G., et al., Biochemistry, 16, 698 (1977).
  8. Jackson, C.M., et al., Biochemistry, 7, 4506 (1968).
  9. Fujikawa, K., Biochemistry, 13, 5290 (1974).
  10. Nagai, K., et al., Proc. Natl. Acad. Sci. USA, 82, 7252 (1985).
  11. Aurell, L., et al., Thromb. Res., 11, 595 (1984).
  12. Nagai, K. and Thogersen, H., Nature, 309, 810 (1984).
  1. Monteiro, S., Biochem. J. (2005) 387, 871–877. (Prothrombin Activation)
  2. Zhang, D., et al., Biochemistry. 2006 November 28; 45(47): 14175–14182. (Prothrombin Activation)
  3. K. Garai et al. / Protein Expression and Purification 66 (2009) 107–112 (Cleavage of fusion proteins)
  4. Kamata, K., et al., Proc. Natl. Acad. Sci. USA, Vol. 95, pp. 6630–6635, June 1998 (Crystallization)
  5. Yang, Y., et al., J Immunol. 2006 December 1; 177(11): 8219–8225. (Used as capture in ELISA)
  6. Krisinger., et al., Journal Biol Chem. (2009) VOL. 284, NO. 9, pp. 5896–5904 (Surface Plasmon Resonance Analysis)
  7. Haynes, L. et al., Arterioscler Thromb Vasc Biol 2012 December pp. 2877-2883 (Factor Xa inhibitor therapies)
  8. Orfeo, T. et al., J Thromb Haemost. 2010 Aug; 8(8): 1745–1753 ((Factor Xa inhibitor therapies)

This publication list is not all encompassing, and is only meant to provide limited examples of how Prolytix products are used. We encourage you to search the literature for other examples pertinent to your experimentation, and to contact us with any technical questions.

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