Production of human PTH(1-34) via a recombinant DNA technique

The production of hPTH(1-34) by site specific chemical cleavage of [Cys35]hPTH(1-84) obtained by a biotechnology technique is described. The amino-peptide bond of S-cyanylated cysteine residues in peptides or proteins is specifically cleaved by exposure to an alkaline solution (Stark, G. R. (1977) Methods Enzymol, 47, 129-132). However, when applying this method to [Cys35]hPTH(1-84), we observed many by-products. Formation of these by-products was suppressed using a short reaction in 0.03N NaOH containing 6M urea at low temperature, and hPTH(1-34) was specifically produced. The product was indistinguishable from standard hPTH(1-34) with respect to chemical and biological characterization.