Abstract A series of deltorphin C (H-Tyr-d-Ala-Phe-Asp-Val-Val-Gly-NH 2) analogues were synthesized to assess the consequences of changing anionic and hydrophobic residues on δ receptor selectivity. Analogues with altered C-terminal groups, inverted sequences, or esterified with tert-butyl, benzyl, or ethyl groups revealed that high δ selectivity required an unmodified amino acid sequence. Shifts of Asp and hydrophobic residues decreased δ ...
[Qian; Shenderovich; Kover; Davis; Horvath; Zalewska; Yamamura; Porreca; Hruby Journal of the American Chemical Society, 1996 , vol. 118, # 31 p. 7280 - 7290]