Abstract
A recently found gastrointestinal hormone, PHI (heptacosapeptide), was synthesized in a different manner from that of Moroder et al. [Z. Naturforsch., 37b, 772 (1982) ]. Our synthesis was carried out by successive azide condensation of six peptide fragments (23-27, 19-22, 15-18, 11-14, 7-10, and 1-6), followed by deprotection with 1 M trifluoromethanesulfonic acid-thioanisole in trifluoroacetic acid. The deprotected peptide was purified by gel-filtration on Sephadex G-25, followed by ion-exchange chromatography on CM-Biogel A and reverse phase high-performance liquid chromatography on μBondapak C18. The homogeneous product thus obtained produced a remarkable decrease in systemic blood pressure in anesthetized rats. In addition, Nα-biotinyl-PHI was synthesized for histochemical receptor-binding studies.
