The fusion protein of Humanized mouse anti-human fibrin ScFv and the low molecuar weight urokinase (IIn-UK) contained seven disulfide bonds and formed inclusion body while expressing in normal E.coli strain.By coexpressing DsbC and using the special E.coli strain Origami(DE3) which was trxB/gor double mutant,the fusion protein IIn-UK was functionally expressed in the cytoplasm of E.coli. The expressed fusion protein in the soluble fraction was purified by using affinity chromatography specific against urokinase. The purified fusion protein could combine the thrombus in vitro ,and the specific activity of urokinase reached 80 000IU/mg fusion protein.The result showed that the fusion protein retained the activity of two moieties,and this study laid a foundation for further research of targeting thrombolytic agent.
