Expression in Escherichia coli of chemically synthesized gene for a novel opiate peptide α-neo-endorphin

Chemically synthesized α-neo-endorphin gene was fused to the Escherlchia coli β-galactosidase gene on the plasmid pKO13. The resulting recombinant DNA was used to transform E. coli cells. Radioimmunoassay for α-neo-endorphin in CNBr-treated bacterial cells showed that α-neo-endorphin was synthesized at approximately 5 × 105 molecules per single E. coli cell. One of the transformants, WA802/pαNE2, was used for α-neo-endorphin purification. From 10.9 g of wet cells, we isolated 4 mg of chemically pure and biologically active α-neo-endorphin.