Journal of Microbial & Biochemical Technology

Abstract

Arabinose Promoter Based Expression of Biologically Active Recombinant Human Growth Hormone in E. coli: Strategies for Over Expression and Simple Purification Methods

Sudheerbabu Soorapaneni, Anjali Apte-Deshpande, Ketaki Sabnis-Prasad, Jitendra Kumar, Veena A Raiker, Prakash Kotwal and Sriram Padmanabhan

An arabinose promoter based expression system in E. coli for the production and purification of recombinant human growth hormone (rhGH) was designed and implemented. The shake flask studies indicated appreciable amounts of rhGH expressed in modified pBAD24 vector (pBAD24M) in comparison to the original pBAD24 vector. While the levels of rhGH reached merely 75 mg l^-1 with pBAD24 in a bioreactor, it reached ~1860 mg l^-1 with pBAD24M vector under similar conditions as judged by densitometry of proteins resolved by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE). The rhGH protein was successfully purified from inclusion bodies after urea denaturation by two simple ion-exchange chromatography steps with an overall recovery of 40% amounting to ~750 mg l^-1 of purified hGH which is the highest reported yield of purified rhGH to date. Such a purified bacterial derived rhGH was characterized by N-terminal sequence, CD spectra studies, mass fingerprint analysis and analysis on Agilent 2100 bioanalyzer. The bioactivity of the purified rhGH was comparable with the commercially available hGH (somatotropin).