title: Isolation and partial characterization of a second myotropic peptide from the hindgut of the cockroach, Leucophaea maderae.
abstract: Proctolin and a second myotropic peptide were extracted from the hindgut of the cockroach Leucophaea maderae with methanol-water-acetic acid (90:9:1). The two peptides were easily separated by HPLC on a mu-Bondapak-phenyl column. Like proctolin, the second peptide was heat stable and was inactivated by the exopeptidases aminopeptidase M and carboxypeptidase Y. The response of the isolated hindgut to the new peptide was distinguishable from the response to proctolin by the following features: (a) a longer interval following application (1-4 min) to reach a maximum contraction, and (b) a much larger amplitude for single phasic contractions. Like proctolin, the new peptide could cause a protracted stimulation of the hindgut for more than 2 hr.
mesh_terms: D000818:Animals; D003058:Cockroaches / Q000502:physiology*; D009119:Muscle Contraction; D009479:Neuropeptides; D018377:Neurotransmitter Agents / Q000302:isolation & purification*; D009842:Oligopeptides / Q000302:isolation & purification; D012995:Solubility
chemical_list: D009479:Neuropeptides; D018377:Neurotransmitter Agents; D009842:Oligopeptides; C011536:proctolin