[Semax and selank inhibit the enkephalin-degrading enzymes from human serum]].

Bioorganicheskaia khimiia2001PMID: 11443939

Plain Language Summary

Shows that Selank and Semax both inhibit enkephalin-degrading enzymes in human serum, with Selank's IC50 at 20 μM—more potent than classical peptidase inhibitors like bacitracin and puromycin. Identifies that the heptapeptide length is critical: shorter fragments lack activity. Proposes enkephalinase inhibition as a shared mechanism for both Selank and Semax's anxiolytic and nootropic effects.

Abstract

A dose-dependent effect of synthetic heptapeptides Semax (Met-Glu-His-Phe-Pro-Gly-Pro) and Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) on the enkephalin-degrading enzymes of human serum was demonstrated. The inhibitory effects of Semax (IC50 10 microM) and Selank (IC50 20 microM) are more pronounced than those of puromycin (IC50 10 mM), bacitracin, and some other inhibitors of peptidases. Beside the heptapeptides, their pentapeptide fragments also possessed an inhibitory effect; tri-, tetra-, and hexapeptide fragments did not display such an effect. As the above enzymes take part in degradation of not only enkephalins but also other regulatory peptides, it can be assumed that one of the mechanisms of biological activity of Semax and Selank is related to this inhibitory activity of theirs.

Authors

Kost, N V; Sokolov, O Iu; Gabaeva, M V; Grivennikov, I A; Andreeva, L A; Miasoedov, N F; Zozulia, A A