Construction, expression, and characterization of recombinant hirudin in Escherichia coli

The mutant gene of HV2-K47 was obtained by polymerase chain reaction-direct ed mutagenesis and expressed in Escherichia coli. Many elements that could affect its expression level were compared. The product was purified to homo geneity via three chromatographic steps-ion exchange, gel filtration, and r everse phase chromatography-on the AKTA Explorer System. The antithrombin a ctivity of HV2-K47 is much higher than that of recombinant HV2. Some proper ties and expression conditions were investigated systematically, which woul d be useful for further studies of hirudin and other small proteins.