Neuropeptide F: primary structure from the tubellarian, Artioposthia triangulata.

1. A neuropeptide exhibiting vertebrate pancreatic polypeptide immunoreactivity has been isolated and sequenced from extracts of the terrestrial turbellarian, Artioposthia triangulata. 2. This neuropeptide, designated neuropeptide F, consists of 36 amino acid residues terminating in a phenylalaninamide. 3. The full primary structure was established as: KVVHLRPRSSFSSEDEYQIYLRNVSKYIQLYGRPRF.NH2. The molecular mass, deduced from this sequence, was 4433 Da. 4. This neuropeptide exhibits C-terminal homology with neuropeptide F (Moniezia expansa) and with the vertebrate neuropeptide Y/pancreatic polypeptide superfamily of which it may represent a phylogenetic precursor.