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Updated: Aug 18, 2026

An Efficient Method for the Synthesis of Peptoids with Mixed Lysine-type/Arginine-type Monomers and Evaluation of Their Anti-leishmanial Activity
Published on: November 2, 2016
[Synthesis and biological activity of a lysine-containing cyclic analog of [Leu5]enkephalin]
Abstract:
The cyclic analogue of [Leu5]enkephalin--cyclo (Lys-Tyr-Gly-Gly-Phe-Leu) and two corresponding linear hexapeptides with lysine residue attached to the N- or C-terminus of the molecule have been synthesized by classical methods of peptide chemistry. The addition of lysine residue to the N-terminus of cyclization of the molecule reduce the interaction of these analogues with both central and peripheral opiate receptors. The addition of lysine residue to the C-terminus of the molecule through the epsilon-amino group does not affect the interaction of the analogue with mu-receptors but reduces approximately tenfold its affinity for delta-receptors. All three analogues have analgesic potency similar to that of [Leu5]enkephalin as assayed after intracisternal administration to mice.
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