• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.2
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• pp.114-121
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• 2012

A novel neuropeptide was isolated from the skin of the snakehead Channa argus using the dorsal retractor muscle (DRM) of a starfish Asterina pectinifera as a bioassay system. The amino acid sequence of the purified peptide was analyzed using automated sequencing and MALDI-TOF mass spectrophotometry. The primary structure of the purified peptide was determined to be Pro-Ala-Leu-Ala-Leu. To investigate the complete primary structure of this peptide, Pro- Ala-Leu-Ala-Leu-OH and Pro-Ala-Leu-Ala-Leu-NH2 were synthesized. The chemical and pharmacological properties of the synthetic peptides were compared with those of the native peptide. Both the native peptide and synthetic Pro-Ala- Leu-Ala-Leu-OH had identical behaviors on the reverse-phase and cation-exchange HPLC chromatograms. Synthetic Pro-Ala-Leu-Ala-Leu-OH showed contractile activity on the DRM, and the threshold concentration of this peptide was approximately $10^{-8}$ M. The maximal contractile effect ($E_{max}$) of this peptide was $294{\pm}45.4$% at $10^{-5}$ M.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.3
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• pp.148-152
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• 2005

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 $120{\pn}7.0\%$ at $10^{-5}M$. The relaxing activity of this peptide on the starfish DRM increased in a dose-dependent manner.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.2
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• pp.129-134
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• 2014

Two neuropeptides were purified from the acidified tube feet extract of the starfish Asterias amurensis by C18 reversed phase and size-exclusion high-performance liquid chromatography (HPLC). The tube feet extract and the purified peptides (AST-I and AST-II) showed potent contractile activity on dorsal retractor muscle (DRM) of the starfish Asterina pectinifera and intestine (smooth muscle) of the panther puffer Takifugu pardalis. Treatment of the purified peptides with dithiothreitol (DTT) for 60 min at $37^{\circ}C$ significantly altered their retention times, suggesting that these compounds contained disulfide bonds. The molecular weights of AST-I and AST-II were determined to be 2064.2 Da and 6137.2 Da, respectively, by MALDI-TOF mass spectrometry.

• Journal of Life Science
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• v.24 no.5
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• pp.491-497
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• 2014

Nowadays, starfish is one of problems about interruption of marine ecosystem, so many researchers are focusing on application of the starfish (Asterias amurensis). In this study, we investigated the contractile and relaxant activity of the smooth muscles and the antimicrobial and antioxidant activity of six different tissues (muscle, gut, liver, tube feet, gonads, and body) of A. amurensis. Frozen samples were extracted with distilled water containing 1% acetic acid. Extracts from all the tissues, except the body tissue, showed potent antimicrobial activity against Escherichia coli D31. The dorsal retractor muscles (DRM) of muscle and gut extracts showed strong contraction responses. On the other hand, contractile activity on esophagus of squid Todarodes pacificus could be detected in all tissues tested. The contractile activity of the liver extract was higher than that of the other tissues. The body, tube feet, and liver extracts showed the contractile activity on the intestine of the panther puffer fish (Takifugu pardalis). Relaxation response on the DRM of starfish (A. pectinifera) was observed in all tissues tested. Increased antioxidant activity was observed in the gut, liver, and body extracts. The results suggest that the starfish (A. amurensis) is a potential source of novel bioactive compounds.