Alternative Synthesis of Substance P

Abstract

A bovine hypothalamic peptide, substance P was synthesized alternatively by successive condensation of three subunits, N-terminal di-, middle hepta- and C-terminal dipeptides. Two newly synthesized peptides, PCA-Phe-Phe-Gly-Leu-Met-NH₂ and PCA-Gln-Phe-Phe-Gly-Leu-Met-NH₂ were both found to be approximately two times active than synthetic substance P, when the contractile activity was determined in isolated guinea-pig ileum.