Orcokinin: a novel myotropic peptide from the nervous system of the crayfish, Orconectes limosus.
A myotropic peptide, named orcokinin, was isolated from approximately 1200 abdominal nerve cords of the crayfish, Orconectes limosus. Its amino acid sequence was determined as follows: Asn-Phe-Asp-Glu-Ile-Asp-Arg-Ser-Gly-Phe-Gly-Phe-Asn. This structure was confirmed by synthesis. There is no sequence similarity to any known neuropeptide. Orcokinin exhibits high potency on the crayfish hindgut, enhancing both frequency and amplitude of spontaneous contractions. The threshold of biological activity in vitro was determined to be approximately 5 x 10(-11) M.
Stangier
J
J
Institut für Zoophysiologie, Rheinischen Friedrich Wilhelms-Universität, Bonn, Germany.
Hilbich
C
C
Burdzik
S
S
Keller
R
R
D000595:Amino Acid Sequence; D000818:Animals; D003400:Astacoidea / Q000737:chemistry* / Q000502:physiology; D004068:Digestive System Physiological Phenomena; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000737:chemistry / Q000302:isolation & purification* / Q000502:physiology
D009479:Neuropeptides; C079067:orcokinin