A. Misicka et al., STRUCTURE-ACTIVITY-RELATIONSHIPS OF ANALOGS OF HIGHLY POTENT OPIOID PEPTIDE BIPHALIN, Regulatory peptides, 1994, pp. 190000131-190000132
For SAR study of biphalin [(Tyr-D-Ala-Gly-PheNH-)(2)] we have synthesi
zed several analogues with modifications of amino acid residues in pos
ition 3 and 4. The introduction of halogenated phenylalanine residues
in position 4 increases affinity to delta receptors. Introducing basic
aromatic amino acid residues in position 4 resulted in decrease in af
finity to mu receptors, but preserve affinity to delta receptors.