HIGH-LEVEL PRODUCTION OF RECOMBINANT HUMAN PARATHYROID-HORMONE-1-34

Expression of the synthetic human parathyroid hormone 1-34 [hPTH(1-34) ] gene by a gene fusion strategy was demonstrated, hPTH(1-34) was prod uced at the C terminus of the partner peptides involving amino acids 1 to 97, 1 to 117, or 1 to 139 of a modified Escherichia coli beta-gala ctosidase by linker peptides containing oligohistidine of different le ngths, The fusion proteins in the inclusion bodies were rendered solub le with urea and subjected to site-specific cleavage with the secretor y type yeast Kex2 protease, Optimal expression and enzymatic processin g were achieved in the fusion protein beta G-117S4HPT, constructed fro m amino acids 1 to 117 of beta-galactosidase and the linker of HHHHPGG SVKKR. The fusion protein accumulated more than 20% of the E. coli tot al protein, The hPTH(1-34) was purified up to 99.5% with a good yield of 0.5 g/liter of culture, The purified product was identified as inta ct hPTH(1-34) by amino acid analysis and N-terminal sequencing.