Identification of two novel peptides from the central nervous system of the desert locust, Schistocerca gregaria.

From an acid methanolic extract of about 7000 brains of the desert locust (Schistocerca gregaria) two novel neuropeptides, schistomyotropin-1 (Scg-MT-1) and schistomyotropin-2 (Scg-MT-2), were isolated and identified. Their primary structures are GAAPAAQFSPRLamide (Scg-MT-1) and TSSLFPHPRLamide (Scg-MT-2). Scg-MT-1 belongs to the locustamyotropin family characterized by its FXPRLamide C-terminus. Scg-MT-2 has a similar carboxyl end with the F-residue one position further away from the C-terminus. This may account for its being 10 times less active then Scg-MT-1 in stimulating cockroach hindgut motility.