T. Takahashi et al., A MYOMODULIN-CARP-RELATED PEPTIDE ISOLATED FROM A POLYCHAETE ANNELID,PERINEREIS-VANCAURICA, Zoological science, 11(1), 1994, pp. 33-38
Myomodulin-CARP-family peptides have been isolated only from molluscs.
In the present study, a heptapeptide, aLa-Met-Gly-Met-Leu-Arg-Met-NH2
, termed Pev-myomodulin, was isolated from a polychaete annelid, Perin
ereis vancaurica using the esophagus of the animal as the bioassay sys
tem. The sequence of the annelid peptide is highly homologous with tho
se of the myomodulin-CARP-family peptides found in molluscs. The annel
id peptide is regarded as a member of the myomodulin-CARP family, thou
gh all the molluscan peptides have a Leu-NH2 at their C-termini. The a
nnelid peptide showed a potnet contractile action on the esophagus of
the annelid. The peptide may be an excitatory neuromediator involved i
n the regulation of the esophagus. Among various myomodulin-CARP-famil
y peptides and their analogues, the annelid peptide showed the most po
tent contractile action on the esophagus. Replacement of the C-termina
l Met-NH, of the annelid peptide with a Leu-NH2 decreased its contract
ile potency, while replacement of the C-terminal Leu-NH2 of myomodulin
and CARP with a Met-NH, increased their potency. The C-terminal Met-N
H, of the annelid peptide seems to be important, but not essential, fo
r exhibiting its contractile activity on the esophagus. On the anterio
r byssus retractor muscle of the bivalve mollusc Mytilus edulis, the a
nnelid peptide showed catch-relaxing and contraction-modulating effect
s qualitatively similar to those of the authentic peptide CARP, though
the annelid peptide was less potent than CARP.