Cytoplasmic inclusion bodies in Escherichia coli producing biosynthetic human insulin proteins.

Escherichia coli that has been genetically manipulated by recombinant DNA technology to synthesize human insulin polypeptides (A chain, B chain, or proinsulin) contains prominent cytoplasmic inclusion bodies. The amount of inclusion product within the cells corresponds to the quantity of chimeric protein formed by the bacteria. At peak production, the inclusion bodies may occupy as much as 20 percent of the Escherichia coli cellular volume.