title: Evaluation of Recombinant Human Growth Hormone Secretion inE. coliusing the L-asparaginase II Signal Peptide.
abstract: BACKGROUND
  In the recent years, there has been an increasing interest in secretory production of recombinant proteins, due to its various advantages compared with intracellular expression. Signal peptides play a critical role in prosperous secretion of recombinant proteins. Accordingly, different signal peptides have been assessed for their ability to produce secretory proteins by trial-and-error experiments. The aim of this study was to evaluate the effect of L-asparaginase II signal peptide on the recombinant human Growth Hormone (hGH) protein secretion in theEscherichia coli (E. coli)host.
  
  
  METHODS
  Cloning and expression of a synthetic hGH gene, containing L-asparaginase II signal sequence was performed inE. coliBL21 (DE3) using 0.1mM IPTG as an inducer at 23°Covernight.Periplasmic protein extraction was performed using three methods, including osmotic shock, osmotic shock in the presence of glycine and combined Lysozyme/EDTA osmotic shock. Afterwards, the hGH expression was determined by SDS-PAGE.
  
  
  RESULTS
  Based on experimentally obtained results, hGH protein is expressed as inclusion body even in the presence of L-asparaginase II signal peptide.
  
  
  CONCLUSIONS
  Therefore, this signal peptide is not effective for secretory production of the recombinant hGH.
authors.affiliation: Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Mozhdeh
authors.initials: M
authors.lastname: Zamani
authors.affiliation: Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Navid
authors.initials: N
authors.lastname: Nezafat
authors.affiliation: Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Younes
authors.initials: Y
authors.lastname: Ghasemi
keywords: Escherichia coli (E. coli); Human growth hormone; L-asparaginase II; Recombinant proteins; Signal peptide