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Coagulation Factor IXa


Activation of Factor X by Factor IXa
The activation of factor X by the intrinsic factor Xase complex is shown. The intrinsic factor Xase complex consists of an enzyme, factor IXa, and a cofactor, factor VIIIa, assembled on a phospholipid surface in the presence of calcium ions. The enzyme complex proteolytically cleaves a 10,000 molecular weight activation peptide from the NH2-terminal of the heavy chain of factor X, thus expressing the active-site of factor Xa.

  • Price $70.00/100 µg ($64.00/min. 5)
    Size 100 µg
    Formulation 50% glycerol/water (v/v)
    Storage -20°C
    Purity >95% by SDS-PAGE
    Activity Determination Factor IX clotting assay
    Shelf Life (properly stored) 12 months
  • Price $78.00/100 µg ($68.00/min. 5)
    Size 100 µg
    Formulation 20 mM Hepes, 150 mM NaCl, pH 7.4
    Storage -80°C
    Purity >95% by SDS-PAGE
    Activity Determination Factor IX clotting assay
    Shelf Life (properly stored) 12 months
  • Price $78.00/100 µg ($68.00/min. 5)
    Size 100 µg
    Formulation 20 mM Hepes, 150 mM NaCl, pH 7.4
    Storage -80°C
    Purity >95% by SDS-PAGE
    Activity Determination Factor IX clotting assay
    Shelf Life (properly stored) 12 months
  • Price $64.00/100 µg ($57.00/min. 5)
    Size 100 µg
    Formulation 50% glycerol/water (v/v)
    Storage -20°C
    Purity >95% by SDS-PAGE
    Activity Determination Factor IX clotting assay
    Shelf Life (properly stored) 12 months
  • Price $70.00/100 µg ($64.00/min. 5)
    Size 100 µg
    Formulation 20 mM Hepes, 150 mM NaCl, pH 7.4
    Storage -80°C
    Purity >95% by SDS-PAGE
    Activity Determination Factor IX clotting assay
    Shelf Life (properly stored) 12 months
  • Price $70.00/100 µg ($64.00/min. 5)
    Size 100 µg
    Formulation 20 mM Hepes, 150 mM NaCl, pH 7.4
    Storage -80°C
    Purity >95% by SDS-PAGE
    Activity Determination Factor IX clotting assay
    Shelf Life (properly stored) 12 months
Gel Novex 4-12% Bis-Tris
Load Human Factor IXa, 1 µg per lane
Buffer MOPS
Standard SeeBluePlus 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)

Factor IXa is produced from its inactive precursor, factor IX, via proteolytic cleavage by factor XIa or the tissue factor/factor VIIa/phospholipid complex. The activation results from the cleavage of two peptide bonds in the factor IX molecule, releasing an activation glycopeptide with an apparent molecular weight of 10,000. The heavy chain of factor IXa (Mr=28,000) contains the serine protease catalytic domain, while the light chain (Mr=17,000) contains the membrane binding domain.

Factor IXa functions as a serine protease involved in the activation of the zymogen, factor X, to form the enzyme, factor Xa. The factor IXa enzymatic activity is greatly enhanced by inclusion of its cofactor, factor VIIIa, in the presence of calcium ions on a phospholipid surface. Factor IXa is readily inhibited by antithrombin III, and this inhibition is greatly accelerated by the presence of heparin. Factor IXa is not inhibited by DFP.

Factor IXa is prepared from highly purified factor IX by activation with factor XIa, as described by Lindquist et al. (5). The factor IXa is further purified by gel filtration, followed by immunoaffinity purification. Factor IXa is also available with the active site irreversibly blocked by the tripeptide chloromethyl ketone, EGRck, or by the fluorescent inhibitor, Dansyl-EGRck. It is supplied in 50% (vol/vol) glycerol/H2O for storage at -20°C. Purity is assessed by SDS-PAGE analysis. Activity is determined in a one-stage clotting assay.

Localization Plasma
Mode of action Enzyme component of the Factor Xase complex
Molecular weight 45,000 (7)
Extinction coefficient
E
1 %
1 c m, 280 nm
= 14.0 (5)
Structure 2 subunits, Mr=28,000 and 17,000 (5), NH2-terminal gla-domain, two EGF domains
Post-translational modifications one b-hydroxyaspartate (3), twelve gla residues (4)
  1. 1. Thompson, A.R., Blood, 67, 565 (1986).
  2. Hedner, U., et al., In Hemostasis and Thrombosis, 2nd edition, ed. R.W. Colman, J. Hirsh, V.J. Marder, E.W.
  3. Salzman, pp., 39-47. J.P. Lippincott Co, Philadelphia, 1987.
  4. Discipio, R.G., et al., Biochemistry, 16, 698 (1977).
  5. McMullen, B.A., et al., BBRC, 115, 8 (1983).
  6. Lindquist, P.A., et al., J. Biol. Chem., 253, 1902 (1978).
  1. Li, Y., Nucleic Acids Research, 2006, Vol. 34, No. 22 (Aptimer interaction)
  2. Neuenschwander, P., et al., J Biol Chem. 2006 August 11; 281(32): 23066–23074. (Active site titration)

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