Production of epidermal growth factor in Escherichia coli from a synthetic gene

Mouse epidermal growth factor (EGF) is under investigation as a deflecting agent for sheep. Substantial quantities of the pure protein are required for these studies and to supply this need a gene for the protein was synthesized and inserted into plasmid vectors to direct the expression of EGF polypeptide, or fusion proteins containing the EGF peptide sequence, in transformed Escherichia coli. Mature EGF was released by lysine specific proteolysis of a fusion protein consisting of part of the E. coli TrpE protein, a lysine linker and EGF polypeptide. The EGF was purified and characterized and was found to be biologically active.