Purification and Characterization of a Novel Neuropeptide with a Smooth Muscle-Relaxing Activity from the Starfish, Asterina pectinifera

摘要

A novel neuropeptide with a relaxing activity on the dorsal retractor muscle (DRM) was isolated from the whole body extract of the starfish, Asterina pectinifera. The peptide was purified by gel-filtration, ion-exchange and C_(18) reversed-phase HPLC.The complete amino acid sequence of this peptide, which was determined by automated Edman degradation and MALDI-TOF mass, was Phe-Gly-Lys-Gly-Gly-Ala-Tyr-Asp-Pro-Leu-Ser-Ala-Gly-Phe-Thr-Asp. A comparison of the amino acid sequence with those of other known neuropeptides revealed that the asteripectin was a novel neuropeptide with smooth muscle-relaxing activity on the starfish DRM, This peptide showed threshold response to relaxing activity on the DRM at 10~(-10)M and the maximal relaxing effect was 120±7.0% at 10~(-5)M, The relaxing activity of this peptide on the starfish DRM increased in a dose-dependent manner.