Expression, purification and characteristic of RGD-hirudin and six mutant versions. (A) Expression and purification of RGD-hirudin and six mutant versions were analyzed by 15% SDS-PAGE. Lane M: molecular mass standards (116 to 14.4 kDa) 20 μL (1 mg/mL) of each sample was loaded on the gel. (B) Anti-thrombin activity of purified RGD-hirudin and six mutant variants. (C) RGD-hirudin and the six mutants have similar effects on rabbit platelet aggregation induced by ADP. The experiments were performed five times with similar results. Error bars represent the standard deviation.