Solute conformation of enkephalin-like pentapeptides in deuterated dimethylsulphoxide.

NMR evidence of the temperature dependence of NH resonances and magnitudes of alpha-CH-NH couplings is advanced in support of preferred beta-bend conformations for five enkephalin-like pentapeptides as solutes in DMSO-d6. The relevance of these and related conformational studies to the interactions of peptides of the enkephalin class with opioid receptors is questioned.