• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.4
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• pp.358-366
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• 2012

A novel neuropeptide was isolated from the skin of the conger eel Conger myriaster using hagfish Eptatretus burgeri intestine as a bioassay system. The sequence of the purified peptide was analyzed using automated amino acid sequencing and MALDI-TOF mass spectrophotometry. The molecular ion peak in the MALDI-TOF mass spectrum of the peptide was at m/z 962.89 $(M+H)^+$. The sequence of the peptide was determined to be L-P-M-L-E-T-Q-M, and was tentatively named comyrin. To investigate the complete primary structure of comyrin, comyrin-OH and comyrin-$NH_2$ were synthesized and the chemical and pharmacological properties of the synthetic peptides were compared with those of the native peptide. However, the elution time of synthetic peptides did not match that of the native peptide on the reverse-phase HPLC chromatogram. In addition, the synthetic peptides did not cause contractile activity in the intestinal smooth muscle of the hagfish. Based on these results, one possible reason for this disagreement may be the presence of a D-amino acid in comyrin.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.1
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• pp.30-34
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• 2003

A hagfish bradykinin(BK)-related peptide was isolated and characterized from the skin of hagfish, Eptatretus burgeri. The hagfish BK with a molecular mass of 875.8 Da was purified to a homogeneity using $C_{18}$ reverse-phase and cation-exchange high performance liquid chromatography. The primary structure of the hagfish BK was determined as Gly-Thr-Ala-Gly-Ile-Gly-Pro-Phe-Arg by a combination of an automated amino acid sequencing and MALDI-TOF mass spectrometry. This amino acid sequence contains five substitutions $(Arg^1{\rightarrow}Gly,\;Pro^2{\rightarrow}Thr,\;Pro^3{\rightarrow}Ala,\;Phe^5{\rightarrow}Ile,\;Ser^6{\rightarrow}Gly)$ compared with that of mammalian BK. The hagfish BK showed a contractile action on the intestine of hagfish, Eptatretus burgeri. The threshold concentration of hagfish BK was around $10^{-11}\;M.$