The present invention discloses a process for the preparation of rhPTH (1-34) also known as
teriparatide by con-struction of a novel
nucleotide, as an NcoI.IXhoI fragemt as set forth in SEQ. ID. No.:1 encoding a chimeric
fusion protein as set forth in SEQ.ID. No.:2 comprising of a fusion partner consisting of 41 amino acids belonging to
Escherichia coli β-galactosidase (LacZ)
gene, an
endopeptidase cleavage site, rhPTH (1-34)
gene fragment,
cloning the said
nucleotide in an
expression vector under the control of T7
promoter, transforming
Escherichia coli with the said vector and expressing the chimeric
fusion protein in fed
batch fermentation. The present invention further discloses a low feed rate
lactose induction for optimized expression of rhPTH (1-34) in
Escherichia coli. The present invention also discloses an unique, novel
two step orthogonal purification process for rhPTH (1-34) comprising of cation exchange
chromatography optionally followed by preparative
chromatography selected from HIC or RP-HPLC to yield a
target protein of ≧99% purity. The present invention discloses a simple, cost-effective, environmentally benign method of producing high purity rhPTH (1-34).