N-TERMINAL MODIFIED ANALOGS OF C-TERMINAL FRAGMENTS OF PBAN WITH PHEROMONOTROPIC ACTIVITY

Various analogs corresponding to the C-terminal portion of pheromone biosynthesis activating neuropeptide of silkmoth, Bombyx mori (Bom-PBAN), were synthesized and tested for pheromonotropic activity. Analogs modified at N-terminal amino group, N-acyl, N-alkyl, D-alanyl and pyroglutamyl hexapeptides, exhibited much greater activity than the corresponding peptides with a free N-terminal amino group. Some of them exhibited higher activity than the unoxidized Bom-PBAN. These blocked peptides were stable in diluted haemolymph from B. mori in vitro, while the non-blocked peptide decomposed rapidly. These results suggest that the stability of the blocked peptides in haemolymph might account for their enhancement of biological activity in the in vivo assay.