Abstract: A recombinant chimeric plasminogen activator(dscuPA) was constructed, consisting of the decorsin(platelet aggregation inhibitor) and a low molecular mass(32 000) single-chain urokinase(scuPA-32k,comprising Leu144 through Leu 411). The structure of the designed protein was predicted and simulated. The recombinant protein was produced in E. Coli after IPTG induction and exited in inclusion body. After refolded in vitro,the chimeric protein was purified by chromatography. The special activity of the chimera was 92 000 IU/mg detected by fibrin plate determination. The chimera could activate plasminogen following Michaelis-Menten kinetics with K_m=1.36 μmol/L and k_cat=0.002 8 s^-1,corresponding to that of scuPA. It was also shown that chimera inhibited ADP-induced platelet aggregation in a concentration dependent manner. These results showed that the chimeric protein not only had high thrombolytic activity but also had anti-thrombus function.

Key words: ScuPA-32k, Decorsin, Platelet aggregation