the purification technique, the activity recovery rate was 56%. After purification, the purity of the product, determined by RP-HPLC, was over 98%, and the specific activity of STH were ×104 IU/mg. The results of SDS-PAGE and Western blot indicated that the linker peptide between SAK and HV2 could be essfully and specifically recognized and cleaved by thrombin. The results of amidolytic assay and fibrin clot lysis assay showed that the N-terminus of HV2 in STH was blocked by staphylokinase and linker peptide, impeding HV2’s anticoagulant activity. Once cleaved, STH displayed % of the anticoagulant activity of equimolar HV2 and exhibited anticoagulant effect in fibrin clot lysis assay. Amidolytic assay and thromboelastogram assay showed that the fibrinolytic activity of STH parable to SAK. Thrombin-binding and fibrin clot lysis assays showed that the C-terminus of HV2 retained its high affinity for thrombin. Moreover, compare with SAK, STH showed improved thrombolytic effects and a lower bleeding risk in animals. Conclusion: A simple, high efficiency of STH production process is established, and the process is easy to scale up. The results in vitro and in vivo study indicate that STH is a promising thrombolytic agent that may have the capacity to display bifunction and thrombus-targeted release of anticoagulant activity in vivo, and thereby reduce the risk of systemic bleeding. 2: Quality control of staphylokinase-hirudin fusion protein, SFH, which linked by FXa recognition peptide Objective: To establish the quality control methods of staphylokinase-hirudin fusion protein, SFH, which linked by FXa recognition peptide. Methods: According to the third pharmacopoeias of the People′s Republic of China (2005) and the relevant directions about biological products, the detection methods of the following items of SFH stock solution were established: the protein concentration was monitored by Lowry method; the purity was detected with non-reducing SDS-PAGE and RP
