. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. S-IAMIDE PEPTIDES OF AN ANNELID 221 t 10"7M AKSGFVRIa 10'6M * I J 5g 2 mm B t JV- * J 10'7M VSSFVRIa t I 10-5M * J 5g Figure 10. Effects of AKSGFVRIamide and VSSFVRIamide on phasic contraction of the ABRM of .\fytilus. The upward arrows indicate application of the peptides. The downward arrows indicate washing-out of the peptides. The phasic contraction was evoked by repetitive electrical pulses (15V. 3 msec, 10 Hz, 50 pulses). Discussion The principal aim of this study was to find out authentic bioactive peptides in an
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. S-IAMIDE PEPTIDES OF AN ANNELID 221 t 10"7M AKSGFVRIa 10'6M * I J 5g 2 mm B t JV- * J 10'7M VSSFVRIa t I 10-5M * J 5g Figure 10. Effects of AKSGFVRIamide and VSSFVRIamide on phasic contraction of the ABRM of .\fytilus. The upward arrows indicate application of the peptides. The downward arrows indicate washing-out of the peptides. The phasic contraction was evoked by repetitive electrical pulses (15V. 3 msec, 10 Hz, 50 pulses). Discussion The principal aim of this study was to find out authentic bioactive peptides in annelids. We isolated two S-Iamide family peptides, AKSGFVRIamide and VSSFVRIamide, from the polychaete annelid, Perinercis. Both the peptides showed a contractile effect on the esophagus of the ani- mal. AKSGFVRIamide is the novel peptide, and VSSFVRIamide has previously been found in the ventral nerve cord of the echiuroid worm, Urechis. S-Iamide pep- tides have been found so far in one species of Echiura and four species of Mollusca (Ikeda et a/.. 1991; Kuroki el 1992; Muneoka and Kobayashi, 1992; in prep, for Anodonta S-Iamide peptide), as listed in Table I. Thus, S-Iamide peptides have been proven to be distributed among at least three invertebrate phyla and may range throughout the Protostomia. The C-termini of the two S-Iamide peptides identified in the current study were concluded to be amidated. though the purified substances were not subjected to fast atom bombardment mass spectrometry. Since the C-ter- mini of all the S-Iamide peptides so far isolated from the echiuroid and molluscs have been known to be amidated. we synthesized AKSGFVRIamide and VSSFVRIamide and compared their behavior on HPLC and contractile activity with those of the purified native peptides. As a result, the identical properties of the native and synthe- sized peptides were confirmed. The synthetic tetra- and pentapeptides, FVRIamide and SFVRIamide, showed only a slight activity for induction
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
