STUDIES ON PEPTIDES .87. SYNTHESIS OF AN OCTACOSAPEPTIDE AMIDE CORRESPONDING TO THE ENTIRE AMINO-ACID-SEQUENCE OF CHICKEN VASOACTIVE INTESTINAL POLYPEPTIDE (VIP)

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  • 1 January 1980
    • journal article
    • research article
    • Vol. 16  (1) , 33-47
Abstract
The octacosapeptide amide corresponding to the entire amino acid sequence of chicken VIP [vasoactive intestinal polypeptide] was synthesized in a conventional manner, using a new Arg derivative, NG-mesitylene-2-sulfonylarginine, Arg(Mts). Treatment of a fragment, p-methoxybenzyloxycarbonyl-Thr-Asp-Asn-Tyr-NHNH2 with methanesulfonic acid or HBr gave a product with a low recovery of Asp, after aminopeptidase digestion. Ring closure of the Asp-Asn unit was responsible for this phenomenon. Deprotection with HF or TFA exhibited definitely less such a tendency. In the final step of the synthesis, all protecting groups, including the Mts group, were removed by HF in the presence of m-cresol and the deprotected peptide was purified by ion-exchange chromatography on CM-cellulose followed by isoelectric focusing in Ampholine pH 9-11. Synthetic peptide exhibited the identical Rf value with that of natural chicken VIP and was active as the natural peptide.