Department of Chemistry and The Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.
J Mass Spectrom. 2010 Jul;45(7):779-87. doi: 10.1002/jms.1768.
The fragmentation reactions of N-monoalkyloxyphosphoryl amino acids (N-MAP-AAs) were studied by electrospray ionization tandem mass spectrometry (ESI-MS). The sodiated cyclic acylphosphoramidates (CAPAs) were formed through a characteristic pentacoordinate phosphate participated rearrangement reaction in the positive-ion ESI-MS/MS and HR-MS/MS of N-MAP-AAs, in which the fragmentation patterns were clearly different from those observed in the corresponding ESI-MS/MS of N-dialkyloxyphosphoryl amino acids/peptides and N-phosphono amino acids. The formation of CAPAs depended on the chemical structures of N-terminal phosphoryl groups, such as alkyloxy group, negative charge and alkali metal ion. A possible integrated rearrangement mechanism for both P-N to P-O phosphoryl group migration and formation of CAPAs was proposed. The fragmentation patterns of CAPAs as novel intermediates in gas phase were also investigated. In addition, it was found that the formation of alpha-amino acid CAPAs was more favorable than beta- or gamma-CAPAs in gas phase, which was consistent with previous solution-phase experiments.
通过电喷雾串联质谱（ESI-MS）研究了 N-单烷氧基磷酰基氨基酸（N-MAP-AAs）的碎裂反应。在 N-MAP-AAs 的正离子 ESI-MS/MS 和 HR-MS/MS 中，通过特征的五配位磷酸参与的重排反应形成了环状酰基磷酰胺酸（CAPAs），其中碎片模式明显不同于相应的 ESI-MS/MS 中观察到的 N-二烷氧基磷酰基氨基酸/肽和 N-膦酸基氨基酸。CAPAs 的形成取决于 N-端磷酸基团的化学结构，如烷氧基、负电荷和碱金属离子。提出了一种可能的 P-N 到 P-O 磷酸基团迁移和 CAPAs 形成的综合重排机制。还研究了气相中 CAPAs 作为新型中间体的碎裂模式。此外，发现在气相中形成α-氨基酸 CAPAs 比β-或γ-CAPAs 更有利，这与先前的溶液相实验一致。
