Identification of a glycogenolysis-inhibiting peptide from the corpora cardiaca of locusts.
A mass spectrometric study of the peptidome of the neurohemal part of the corpora cardiaca of Locusta migratoria and Schistocerca gregaria shows that it contains several unknown peptides. We were able to identify the sequence of one of these peptides as pQSDLFLLSPK. This sequence is identical to the part of the Locusta insulin-related peptide (IRP) precursor that is situated between the signal peptide and the B-chain. We designated this peptide as IRP copeptide. This IRP copeptide is also present in the pars intercerebralis, which is likely to be the site of synthesis. It is identical in both L. migratoria and S. gregaria. It shows no effect on the hemolymph lipid concentration in vivo or muscle contraction in vitro. The IRP copeptide is able to cause a decreased phosphorylase activity in locust fat body in vitro, opposite to the effect of the adipokinetic hormones and therefore possibly represents a glycogenolysis-inhibiting peptide.
Clynen
Elke
E
Laboratory for Developmental Physiology and Molecular Biology, Katholieke Universiteit Leuven, 3000 Leuven, Belgium. Elke.Clynen@bio.kuleuven.ac.be
Huybrechts
Jurgen
J
Baggerman
Geert
G
Van Doorn
Jan
J
Van Der Horst
Dick
D
De Loof
Arnold
A
Schoofs
Liliane
L
D000595:Amino Acid Sequence; D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006003:Glycogen / Q000378:metabolism*; D024981:Glycogen Phosphorylase / Q000037:antagonists & inhibitors; D006110:Grasshoppers; D007301:Insect Hormones / Q000494:pharmacology; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000032:analysis* / Q000737:chemistry / Q000494:pharmacology; D009490:Neurosecretory Systems / Q000737:chemistry*; D011498:Protein Precursors / Q000737:chemistry; D020539:Sequence Analysis, Protein; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D004791:Enzyme Inhibitors; D007301:Insect Hormones; D009479:Neuropeptides; D011498:Protein Precursors; C014956:adipokinetic hormone (locust); D006003:Glycogen; D024981:Glycogen Phosphorylase