Protein production by stationary phase induction (SPI).

An alternative method for expressing the recombinant proteins in Escherichia coli is proposed. Unlike the ordinary induction protocol where the cells in the early- to mid-log phase are induced for the protein production, this alternative protocol utilizes the cells in the stationary phase. By using a glutathione S-transferase fusion protein as an example, the protocol proposed in this report yielded a higher amount of the desired protein than that from the ordinary protocol. This protocol also suppressed the proteolytic cleavage of the desired protein in the Escherichia coli cytoplasm, thus it should be particularly useful to produce proteins that undergo unwanted cleavages.