Alternative Synthesis of Porcine Secretin and Apparent Autolysis of the Product

Abstract

Porcine secretin was synthesized by the trifluoromethanesulfonic acid deprotecting procedure. Release of the biologically important His¹-residue from synthetic secretin was noted when the secretin was incubated in an aqueous solution at 37°C under nearly neutral conditions. Apparent autolysis of the N-terminal tetrapeptide, His-Ser-Asp-Gly, was examined by using 5 peptide analogs, and the participation of the β-carboxyl group of Asp and the basic amino acid, His, in this unusual phenomenon was deduced. Hydrolysis of the peptide bonds between Asp-Ser (15-16) and Asp-Gly (3-4) was also noted when the above incubated solution was examined by high performance liquid chromatography.