Eight peptide fragments were prepared by known amide-forming reactions as building blocks for the solution synthesis of the dotetracontapeptide corresponding to the entire amino acid sequence of human intestinal GIP (gastric inhibitory polypeptide or glucose-dependent insulinotropic polypeptide). Besides Lys(Z), Trp(Mts) and Gln-OBzl, two new amino acid derivatives, Asp(OChp) and Glu(OChp) [Mts=mesitylenesulfonyl, Chp=cycloheptyl], were employed to suppress various side reactions. These fragments were successively assembled by the azide procedure to minimize racemization and all protecting groups employed were removed from the protected GIP by using 1M trifluoromethanesulfonic acid-thioanisole in trifluoroacetic acid.Synthetic GIP exhibited a significant glucose-dependent insulinotropic activity in dogs, but failed to produce any notable anti-gastric activity in rats.
八个肽段通过已知的
酰胺形成反应作为构建块,用于合成对应于人类肠道GIP(胃抑制
多肽或
葡萄糖依赖性
胰岛素促进肽)完整
氨基酸序列的四十肽。此外,除了Lys(Z)、Trp(Mts)和Gln-OBzl,还使用了两个新的
氨基酸衍
生物Asp(OChp)和Glu(OChp) [Mts=美克
烯磺酰基,Chp=环庚基],以抑制各种副反应。这些肽段通过
叠氮化程序逐步组合,以最小化消旋化,所有使用的保护基团均通过在
三氟乙酸中使用1M三
氟甲烷磺酸-
硫代
苯醚去除。合成的GIP在犬中表现出显著的
葡萄糖依赖性
胰岛素促进活性,但未能在大鼠中产生任何显著的抗胃活性。