β^1–16‐Corticotropin‐methylester

Abstract

Abstract The synthesis of β 1–16 ‐corticotropin methyl ester is described( 14 ). As in previous work from these laboratories, t ‐butyl‐ and t ‐butoxycarbonyl groups were employed for the protection of side chain carboxyl and amino groups, respectively. This warrants excellent yields in the critical last step of the synthesis of large polypeptides: the removal of blocking groups. The compound was shown to be pure by thin layer chromatography on silicagel, by electrophoresis on paper, by amino‐acid analysis, and by digestion of the total hydrolysate with L ‐amino‐acid oxidase of snake venom. The ACTH‐activity displayed was 5–10 U/mg in the in vitro assay of Saffran & Schally( 4 ) and less than 1 USP‐U/mg in the subcutaneous test according to Sayers( 5 ) (solution in 1% gelatin).