Rubini Chiara, Osler Alessio, Calderan Andrea, Guiotto Andrea, Ruzza Paolo
Institute of Biomolecular Chemistry of CNR, Padua Unit, 35131 Padua, Italy.
J Pept Sci. 2008 Aug;14(8):989-97. doi: 10.1002/psc.1032.
Unusual TFA catalyzed cleavage reaction is reported for peptide containing pipecolic acid residues. Although the use of TFA under standard cleavage conditions is sufficiently mild to prevent degradation of the desired products, the amide bond between consecutive pipecolic acid residues is unexpectedly hydrolyzed by standard TFA treatment. The hydrolysis is proposed to proceed via an oxazolinium ion intermediate. This mechanism is supported by H/D exchange as observed by ESI-MS and NMR experiments.
据报道，含哌啶酸残基的肽发生了不寻常的三氟乙酸（TFA）催化裂解反应。尽管在标准裂解条件下使用TFA足够温和，可防止所需产物降解，但连续哌啶酸残基之间的酰胺键在标准TFA处理下意外水解。有人提出水解是通过恶唑啉离子中间体进行的。电喷雾电离质谱（ESI-MS）和核磁共振（NMR）实验观察到的氢/氘交换支持了这一机制。
