High-level production and one-step purification of biologically active human growth hormone in Escherichia coli.

A plasmid has been constructed to direct the synthesis of recombinant human growth hormone (re-hGH) in Escherichia coli as a fusion protein containing a His6 tag at the N-terminus under the control of the T5 promoter. The re-hGH was synthesized in large amounts and accumulated in the form of inclusion bodies upon induction with IPTG. Inclusion bodies were solubilized in 6 M guanidine.HCl and the re-hGH was purified by single-step affinity chromatography on Ni(2+)-nitrilotriacetic acid (NTA) agarose. At the shake flask level, the purified re-hGH was obtained with a yield of 30 mg/l of culture. The re-hGH was biologically active in a node rat lymphoma (Nb2) cell bioassay.