Renaturation and purification of recombinant tissue-type plasminogen activator expressed in E. coli

Under the control of trp promoter, human tissue-type plasminogen activator was expressed in E. coli in the form of inclusion body. The recombinant t-PA was recovered for renaturation from preparative native PAGE, gel by zinc acetate staining and electroelution. After renaturation in vitro, the recombinant t-PA was purified by benzamidine affinity chromatography and lysine affinity chromatography. The purified t-PA showed homogeneous on silver-stained SDS-PAGE gel, with a specific activity of 240,000 I.U./mg protein.