Purification Of Factors IX And X From Clinical Concentrate

Human factors IX and X have been purified to homogeneity from clinical factor IX concentrate that had been rejected for therapeutic use due to particulate contamination. (It was necessary to start with this material since in the UK, plasma is not commercially available). The procedure involved barium citrate adsorption followed by ammonium sulphate elution, DEAE- cellulose chromatography, gel filtration on Sephacryl S-200 and affinity chromatography on heparin sepharose gel. The preparation of factor IX at this stage showed a single band on SDS-polyacrylamide gel electrophoresis, of molecular weight 58,000. No change in molecular weight was observed in the presence of 2-mercaptoethanol. A further affinity chromatography column - poly (homoarginine) Sepharose or dextran sulphate sepharose - was necessary to obtain homogeneous factor X. The preparation obtained showed a single band on SDS-polyacrylamide gel electrophoresis of molecular weight 67,000. In the presence of 2-mercaptoethanol, two bands were obtained of molecular weights 49000 and 17000 representing the heavy and light chains respectively of factor X. The purified coagulation proteins contained no activated species detectable by nonactivated partial thromboplastin time or by chromogenic substrate (S2222) assay. Prothrombin protein Sand protein C are by-products of this purification procedure.