PRIMARY STRUCTURE OF A NEW NEUROPEPTIDE, CEREBRAL-PEPTIDE-2, PURIFIEDFROM CEREBRAL GANGLIA OF APLYSIA

We report the purification and characterization of a novel neuropeptid e from Aplysia nervous tissue. The peptide was termed cerebral peptide 2 (CP2) because it was the larger of two peptides predominantly synth esized in the cerebral ganglia and transported to other regions of the central nervous system. The purification of CP2 from extracts of cere bral ganglia using three sequential modes of high-pressure liquid chro matography (HPLC) was followed using the [S-35]methionine-labeled pept ide obtained from transport experiments. The primary structure of CP2 was determined by automated Edman degradation of native CP2 and its pr oteolytic fragments in conjunction with mass spectrometry. CP2 is a 41 amino acid peptide with an amidated carboxyl terminal. A peptide with the proposed sequence of CP2 was synthesized and compared by HPLC wit h the native peptide. Chromatographic properties of the synthetic and native peptide labeled in vivo were found to be identical. CP2 does no t appear to be a member of any previously identified peptide family.