PARTIAL-PURIFICATION OF THROMBOPOIETIN FROM THE PLASMA OF THROMBOCYTOPENIC RABBITS

  • 1 January 1979
    • journal article
    • research article
    • Vol. 54  (2) , 377-388
Abstract
Partially purified thrombopoiesis-stimulating activity was prepared from the plasma of thrombocytopenic rabbits using ammonium sulfate precipitation and DEAE cellulose, Sephadex and CM cellulose chromatography. The protein fraction precipitated by an ammonium sulfate saturation of 60-80%, which contain thrombopoiesis-stimulating activity, was used as starting material. Column chromatography was carried out at room temperature at pH 5.6. Under these conditions, thrombopoiesis-stimulating activity (thrombopoietin) was retained by DEAE cellulose (0.03 M citrate-phosphate buffer) and carboxymethyl cellulose (0.003 M citrate-phosphate buffer), and eluted with 0.4 M NaCl. Thrombopoietin was retarded by Sephadex G-100; the ratio of the elution volume to the void volume was 1.32:1. Immunoelectrophoretic analysis of partially purified thrombopoietin indicated that following removal of most of the albumin by DEAE chromatography, only proteins with the mobilities of .beta.-globulins and albumin and traces of other anodally migrating proteins were detectable in the fractions that contained thrombopoiesis-stimulating activity. Thrombopoietin was not dialyzable and was stable from at least pH 5.6-7.5. It was approximately 1000-fold purified following sequential chromatography with DEAE and CM cellulose. Although the 3 fractions described reproducibly stimulated thrombopoiesis, as measured by increased levels of selenome-thionine 75Se (75SeM) in the circulating platelets, platelet counts did not increase.