Pseudopeptide CCK-4 analogues incorporating the Ψ[CH(CN)NH] peptide bond surrogate

Abstract

The synthesis, binding to CCK receptors, and in vitro functional activity of pseudopeptide CCK-4 analogues incorporating the ( R) or ( S) Ψ[CH(CN)NH] peptide bond surrogate at the NIe 31-Asp 32or or Trp 30-NIe 13 bonds are described. Z-TrpΨ[( S)CH(CN)NH]NIe-Asp-Phe-NH 2 retained the high CCK-B receptor binding affinity of Boc-[NIe 31]-CCK-4, and was a potent and selective CCK-B antagonist in the isolated guinea pig ileum.