Isolation of L-3-phenyllactyl-Leu-Arg-Asn-NH2 (Antho-RNamide), a sea anemone neuropeptide containing an unusual amino-terminal blocking group.
Using a radioimmunoassay for the carboxyl-terminal sequence Arg-Asn-NH2, we have purified a peptide from acetic acid extracts of the sea anemone Anthopleura elegantissima. By classical amino acid analyses, mass spectrometry, and 1H NMR spectroscopy, the structure of this peptide was determined as 3-phenyllactyl-Leu-Arg-Asn-NH2. By using reversed-phase HPLC and a chiral mobile phase, it was shown that the 3-phenyllactyl group had the L configuration. Immunocytochemical staining with antiserum against Arg-Asn-NH2 showed that L-3-phenyllactyl-Leu-Arg-Asn-NH2 (Antho-RNamide) was localized in neurons of sea anemones. The L-3-phenyllactyl group has not been found earlier in neuropeptides of vertebrates or higher invertebrates. We propose that this residue renders Antho-RNamide resistant to nonspecific aminopeptidases, thereby increasing the stability of the peptide after neuronal release.
Grimmelikhuijzen
C J
CJ
Center for Molecular Neurobiology, University of Hamburg, Federal Republic of Germany.
Rinehart
K L
KL
Jacob
E
E
Graff
D
D
Reinscheid
R K
RK
Nothacker
H P
HP
Staley
A L
AL
D000595:Amino Acid Sequence; D000818:Animals; D000918:Antibody Specificity; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003063:Cnidaria; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000302:isolation & purification*; D009842:Oligopeptides / Q000138:chemical synthesis; D011863:Radioimmunoassay; D012615:Sea Anemones; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
D009479:Neuropeptides; D009842:Oligopeptides; C064978:3-phenyllactyl-leucyl-arginyl-asparaginamide