Isolation and characterization of schistostatin-2(11-18) from the desert locust, Schistocerca gregaria: a truncated analog of schistostatin-2

Regul Pept. 1996 Dec 17;67(3):195-9. doi: 10.1016/s0167-0115(96)00131-0.

Abstract

An octapeptide was isolated from 7000 brains of the desert locust. Schistocerca gregaria by screening of HPLC fractions using a RIA for Dip-AST-2 (allatostatin-2 from the cockroach). Maldi-TOF-MS revealed a mass of 921.4 Da. The primary structure of the peptide is LPVYNFGL-NH2. It is identical to the C-terminal portion of schistostatin-2 from Schistocerca gregaria. Therefore, it was designated Scg-AST-2(11-18). The chromatographic properties of the synthetic peptide are identical to these of the native peptide. The peptide is a truncated product of Scg-AST-2, suggesting that an endopeptidase which cleaves between Arg and Leu is present in the brain complex of S. gregaria. Although, Scg-AST-2(11-18) contains the same C-terminus as Dip-AST-2, it has no inhibitory activity on the corpora allata (CA) of 2-day-old virgin females of D. punctata. This suggests that Scg-AST2 (11-18) may be the result of a proteolytic inactivation mechanism and/or that it may be involved in stage-dependent down regulation of allatostatic activity. To our knowledge, Scg-AST-2 is the first isolated peptide which has the active core of the allatostatin peptide family but nevertheless shows no activity in this bioassay.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amino Acids / analysis
  • Animals
  • Chromatography, High Pressure Liquid
  • Cockroaches / drug effects
  • Corpora Allata / drug effects
  • Corpora Allata / metabolism
  • Dose-Response Relationship, Drug
  • Grasshoppers / chemistry*
  • Insect Proteins / chemistry*
  • Insect Proteins / isolation & purification*
  • Insect Proteins / pharmacology
  • Juvenile Hormones / biosynthesis
  • Molecular Sequence Data
  • Neuropeptides / chemistry*
  • Neuropeptides / isolation & purification*
  • Neuropeptides / pharmacology
  • Peptides / chemistry
  • Peptides / isolation & purification
  • Sequence Analysis

Substances

  • Amino Acids
  • Insect Proteins
  • Juvenile Hormones
  • Neuropeptides
  • Peptides
  • schistostatin