New <i>N</i>‐terminal modified proctolin analogues

Abstract

Five proctolin analogues modified in position 1 of the peptide chain by Cit (I), Lys (II), His (III), Phe(p‐NH 2 ) (IV) and γ‐Abu (V) were synthesized by conventional liquid phase method. Biological activity of the obtained peptides was investigated by the cardioexcitatory test on two insect species, cockroach, Periplaneta americana L. and yellow mealworm, Tenebrio molitor L.