Synthesis of [4,5-dehydroLeu2]- and [3,4-dehydropro6]-locust adipokinetic hormone

Abstract

The syntheses of [4,5-dehydroLeu²]- and [3,4-dehydroPro⁶]-locust adipokinetic hormone (LAKH) by the coupling of N-terminal hexapeptides prepared by the solid-phase method with a common C-terminal tetrapeptide synthesised in solution is described. At a dose level of 20 pmol, the former is at least as biologically active as LAKH, but the latter has only ca. 20% of the activity. Difficulties encountered in the incorporation of a 4,5-dehydroleucine residue into peptides are discussed.