Conformation of a diastereoisomeric pair of enkephalin analogues: A 400 MHz 1H NMR study

This is the authors' abstract. We don't add key points for this paper.

Abstract 1H NMR spectra recorded at 400 MHz of the enkephalin analogues Tyr‐D‐NIe‐Gly‐Phe‐D(and L)‐NIeS and the dipeptide Ac‐Phe‐D‐NIeS as solutes in DMSO‐d6 are reported and assigned. A preferred conformation of the D2L5 peptide is proposed, based on evidence of an intramolecular hydrogen bond between Phe4 NH and Tyr1 CO and NH/a‐CH coupling constants. The possibility of conformational differences between the isomeric peptides accounting for differences in their ability to bind to δ‐opiate receptors is discussed.