A new method for the preparation of human parathyroid hormone 1-34 peptides.

An engineered Escherichia coli strain, BL21 (DE3)/pGEX-4T-human parathyroid hormone (hPTH) (1-34), was constructed by oligonucleotide annealing and PCR amplification of the target gene, and then by ligating it with the pGEX-4T-3 vector and transferring into the BL21 host. The soluble glutathione S-transferase (GST) fusion protein GST-hPTH (1-34), expressed from BL21 (DE3)/pGEX-4T-hPTH (1-34), was harvested after fermentation and purification by affinity chromatography. Following double cleavage by thrombin and prolyl endopeptidase, about 0.6 g/l intact hPTH (1-34) was harvested. The product was checked by HPLC MS and N-terminal sequence analysis. The purified recombinant hPTH (1-34) stimulates adenylate cyclase in rabbit renal cortical cell membranes to exactly the same extent as synthetic hPTH standards, indicating that the recombinant product has full biological activity.