Studies on peptides. CXXXIX Solution synthesis of a 42-residue peptide corresponding to the entire amino acid sequence of human glucose-dependent insulinotropic polypeptide (GIP).
Studies on peptides. CXXXIX Solution synthesis of a 42-residue peptide corresponding to the entire amino acid sequence of human glucose-dependent insulinotropic polypeptide (GIP).
Studies on peptides. CXLI Synthesis of a 42-residue peptide corresponding to the entire amino acid sequence of porcine GIP (glucose-dependent insulinotropic polypeptide).
The dotetracontapeptide corresponding to the revised amino acid sequence of porcine GIP (glucose-dependent insulinotropic polypeptide; originally named gastric inhibitory polypeptide) was synthesized by assembling eight peptide fragments of established purity, followed by thioanisole-mediated deprotection with trifluoromethanesulfonic acid in trifluoroacetic acid. The cycloheptyl esters of aspartic acid and glutamic acid were employed to suppress base-catalyzed side reactions. When tested in dogs, the synthetic peptide produced a significant increase of immunoreactive insulin in blood under background infusion of glucose.