SYNTHESIS OF A 42 RESIDUE PEPTIDE CORRESPONDING TO THE ENTIRE AMINO ACID SEQUENCE OF HUMAN GIP

Abstract

Human GIP (gastric inhibitory polypeptide or glucose-dependent insulinotropic polypeptide) was synthesized in a conventional solution method by assembling eight peptide fragments followed by deprotection with 1 M trifluoromethanesulfonic acid-thioanisole in trifluoroacetic acid. New amino acid derivatives, Trp (Mts), Asp (OChp), and Glu (OChp) [Mts=mesitylenesulfonyl, Chp=cycloheptyl] were employed to suppress various side reactions. Synthetic GIP exhibited a significant increase of immunoreactive insulin level in dog plasma under basal ground infusion of glucose.