[Expression and purification of recombinant human cytochrome C in Escherichia coli]

Cytochrome C plays important roles in electron transferring, oxidative stress and apoptosis. In this study, soluble cytochrome C was accumulated in cytoplasm of E. coli by utilizing the co-expression of human cytochrome c and yeast heme lyase from a single plasmid. After ultrasonic disruption of the bacteria, a lot of contaminated proteins were discarded by addition of 350 g/L ammonium sulfate into the supernatant. Then the recombinant human cytochrome C was purified to 80% homogeneity after two times cation exchange chromatography on SP-Sepharose Fast Flow. Yields of cytochrome C greater than 10 mg per liter culture were attained. This efficient system for producing human cytochrome C is helpful for us to understand the roles of this protein in biological processes and therapy of human diseases relevant to apoptosis and oxidative stress.