Production of human proinsulin inE. coli in a non-fusion form

Summary A method for direct expression of the gene encoding human proinsulin inE. coli and a simple purification procedure has been established. The temperature inducible promoter is employed for rapid induction as well as high level expression, After simple down-stream processing, 80–160mg recombinant product with a purity of up to 90% can easily be obtained from 1 liter of high density fermentation medium by a single Sephadex G50 column.