Minigastrin; corrected structure and synthesis.

Evidence is presented that minigastrin is the C-terminal tetradecapeptide amide of gastrin and not the tridecapeptide amide as previously reported. Synthesis of the tetradecapeptide amide sequence, Trp-Leu-[Glu]5-Ala-Tyr-Gly-Trp-Met-Asp-Phe-Nh2, was achieved by a series of fragment couplings which were mediated by the dicyclohexylcarbodiimide procedure in presence of either N-hydroxysuccinimide or 1-hydroxybenzotriazole. Purification of all intermediate fragments, and of the final protected tetradecapeptide amide, was by Sephadex LH-20 chromatography. Removal of the protecting groups was effected by treatment with 90% trifluoroacetic acid in the presence of a large excess of scavengers. Purification by ion-exchange chromatography afforded the pure tetradecapeptide amide. This material had full physiological activity.