Biological activity of fragments and analogues of the potent dimeric opioid peptide, biphalin

Abstract The synthesis and biological activity of two fragments of the very potent opioid peptide biphalin, showed that Tyr-D-Ala-Gly-Phe-NH-NH The synthesis and biological activity of the truncated analogues of the very potent opioid peptide biphalin are reported. The study showed the minimal fragment necessary to express equal affinities and biological activity profile as the parent biphalin is: Tyr-D-Ala-Gly-Phe-NH-NH