ISOLATE AND TEST HUMAN ANTITHROMBIN-III (HEPARIN COFACTOR)

摘要

A two-stage assay, using purified substrates, was developed for measuring the antithrombin-III activity (Heparin cofactor) of human Cohn Fractions.nThe first step involved incubation of the antithrombin-III containing sample with bovine thrombin in the presence of heparin, and the second step quantitated the residual thrombin activity by measuring its clotting time with human fibrinogen. A unit of antithrombin-III biological activity was defined as the amount which inhibited one unit of thrombin. In addition to the activity assays,antithrombin-III levels of the Cohn fractions were detected by Ouchterlony double gel difussion. Both assays identified Cohn Fraction IV-1 as the prime starting material for anti¬thrombin-III isolations. The antithrombin-III was isolated from the starting material by affinity chromatography on heparin-agarose.