title: Isolation of two novel neuropeptides from sea anemones: the unusual, biologically active L-3-phenyllactyl-Tyr-Arg-Ile-NH2 and its des-phenyllactyl fragment Tyr-Arg-Ile-NH2.
abstract: Using a radioimmunoassay for the carboxyl-terminal sequence Arg-Val-NH2, two novel peptides were purified from extracts of the sea anemone Anthopleura elegantissima. These peptides were L-3-phenyllactyl-Tyr-Arg-Ile-NH2 (name: Antho-RIamide I) and its des-phenyllactyl fragment Tyr-Arg-Ile-NH2 (Antho-RIamide II). Immunocytochemical staining showed that these peptides were localized in neurons of sea anemones. Application of low concentrations (10(-8) M) of Antho-RIamide I inhibited spontaneous contractions in several muscle groups of sea anemones, whereas Antho-RIamide II was inactive. Antho-RIamide I is the second neuropeptide from sea anemones that bears the unusual, amino-terminal L-3-phenyllactyl blocking group. We suggest that this group renders the peptide resistant agaist degradation by nonspecific aminopeptidases. In addition, the L-3-phenyllactyl residue might also play a role in receptor binding.
authors.affiliation: Center for Molecular Neurobiology (ZMNH), University of Hamburg, Federal Republic of Germany.
authors.forename: H P
authors.initials: HP
authors.lastname: Nothacker
authors.forename: K L
authors.initials: KL
authors.lastname: Rinehart
authors.forename: I D
authors.initials: ID
authors.lastname: McFarlane
authors.forename: C J
authors.initials: CJ
authors.lastname: Grimmelikhuijzen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D008969:Molecular Sequence Data; D009119:Muscle Contraction / Q000187:drug effects; D009479:Neuropeptides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D009842:Oligopeptides / Q000737:chemistry / Q000302:isolation & purification*; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D012615:Sea Anemones / Q000737:chemistry*
chemical_list: D009479:Neuropeptides; D009842:Oligopeptides; D010446:Peptide Fragments; C074612:Antho-RIamide I; C074614:Antho-RIamide II