Studies on Peptides. CXLVII. Synthesis of Valosin, a Novel 25-Residue Peptide from Porcine Intestine

Abstract

A 25-residue peptide isolated from porcine intestine, designated valosin, was synthesized by assembling seven peptide fragments of established purity, followed by deprotection with 1 M trifluoromethanesulfonic acid in trifluoroacetic acid. γ-Cycloheptylglutamate, [Glu (OChp)], was employed to suppress pyrrolidone formation during fragment condensation. Before deprotection, Met (O) was reduced with phenylthiotrimethylsilane and trimethylsilyl trifluoromethanesulfonate. The effect of the synthetic peptide on arterial pressure, blood flow in the superior mesenteric artery, pancreatic capillary blood flow and pancreatic exocrine secretion was examined in dogs, but no significant dose-dependent response was observed. In rats, synthetic valosin stimulated pancreatic secretion, but showed no anti-gastric activity.