Boc-, Fmoc- and Cbz-protected isocysteine building blocks were prepared by a concise three-step procedure starting from thiomalic acid. The use of Boc/Trt-protected isocysteine provided convenient access to isocysteinyl peptides that allow the chemoselective ligation of unprotected peptide fragments in water. The pH-dependency of the isocysteine-mediated ligation was compared with that of cysteine-mediated native chemical ligation.
以
硫代
苹果酸为起点,通过简洁的三步法制备出 Boc、Fmoc 和 Cbz 保护的异半胱
氨酸构筑模块。使用 Boc/Trt 保护的异半胱
氨酸可以方便地获得异半胱
氨酸肽,从而可以在
水中对未受保护的肽片段进行
化学选择性连接。比较了异半胱
氨酸介导的连接与半胱
氨酸介导的原生
化学连接的 pH 依赖性。