Primary Structure of Allatostatin 4, a Nevropeptide Inhibitor of Juvenile Hormone Synthesis

Abstract

Isolation and identification of allatostatin 4 (AST 4) from crude brain extracts of female Diploptera punctatu are described. Synthetic analogues of allatostatin 4 truncated from the N-terminal were evaluated to gain some knowledge of structure-activity correlation. AST 4 reversibly inhibits the biosynthesis of JH in vitro. AST 4 has the following sequence : Asp-Arg-Leu-Tyr-Ser-Phe-Gly-Leu-NH2.This neurohormone (AST 4) has no sequence similarity with any known neuropeptide from other organisms. Synthetic AST 4 as well as truncation fragments, including two with the five and six amino acids terminal residues deleted showed in vitro activity distinguishable from that of the native allatostatin.