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.

Haemtech生物制药服务（HBS）是一家领先的，符合cGMP要求的QC测试实验室，专门为生产重组和血浆衍生蛋白疗法的生物制药制造商提供分析服务，重点是那些会影响止血系统的药物。HBS使客户能够满足法规和质量测试要求，从而将其候选药物从开发转向商业化。

对生物制药的需求正在增长，并且该行业正在迅速采用外包策略，以作为满足不断升级的监管要求的一种方式。凭借在止血方面的丰富经验，HBS能够很好地协助开发影响凝血系统的药物产品。