Solid phase synthesis of a 31-residue fragment of human glucose-dependent insulinotropic polypeptide (GIP) by the continuous flow polyamide method.

A fragment, GIP1-31, of the human Glucose-dependent Insulinotropic Polypeptide (GIP1-42) Tyr-Ala-Glu-Gly-Thr-Phe-Ile-Ser-Asp-Tyr-Ser-Ile-Ala-Met-Asp-Lys-Ile-His- Gln-Gln-Asp-Phe-Val-Asn-Trp-Leu-Leu-Ala-Gln-Lys-Gly has been synthesized by solid phase methodology under continuous flow conditions. The peptide was assembled on a polydimethylacrylamide kieselguhr support by using 9-fluorenylmethoxycarbonyl amino acid pentafluorophenyl esters. The crude peptide, obtained after trifluoroacetic acid cleavage, was purified by gel filtration and by reverse-phase HPLC. This synthetic replicate, corresponding to human GIP1-31, retains the ability of naturally occurring GIP to stimulate insulin release.