Moyer Susanne C, Cotter Robert J, Woods Amina S
Department of Chemistry, Johns Hopkins University, Baltimore, Maryland, USA.
J Am Soc Mass Spectrom. 2002 Mar;13(3):274-83. doi: 10.1016/S1044-0305(01)00361-0.
An investigation of phosphate loss from phosphopeptide ions was conducted, using both atmospheric pressure matrix-assisted laser desorption/ionization (AP MALDI) and electrospray ionization (ESI) coupled to an ion trap mass spectrometer (ITMS). These experiments were carried out on a number of phosphorylated peptides in order to investigate gas phase dephosphorylation patterns associated with phosphoserine, phosphothreonine, and phosphotyrosine residues. In particular, we explored the fragmentation patterns of phosphotyrosine containing peptides, which experience a loss of 98 Da under collision induced dissociation (CID) conditions in the ITMS. The loss of 98 Da is unexpected for phosphotyrosine, given the structure of its side chain. The fragmentation of phosphoserine and phosphothreonine containing peptides was also investigated. While phosphoserine and phosphothreonine residues undergo a loss of 98 Da under CID conditions regardless of peptide amino acid composition, phosphate loss from phosphotyrosine residues seems to be dependent on the presence of arginine or lysine residues in the peptide sequence.
利用大气压基质辅助激光解吸/电离（AP MALDI）和电喷雾电离（ESI）与离子阱质谱仪（ITMS）联用，对磷酸肽离子中的磷酸盐损失进行了研究。对多种磷酸化肽进行了这些实验，以研究与磷酸丝氨酸、磷酸苏氨酸和磷酸酪氨酸残基相关的气相去磷酸化模式。特别是，我们探索了含磷酸酪氨酸肽的碎裂模式，这些肽在ITMS的碰撞诱导解离（CID）条件下会损失98 Da。鉴于磷酸酪氨酸侧链的结构，其损失98 Da是出乎意料的。还研究了含磷酸丝氨酸和磷酸苏氨酸肽的碎裂情况。虽然无论肽的氨基酸组成如何，磷酸丝氨酸和磷酸苏氨酸残基在CID条件下都会损失98 Da，但磷酸酪氨酸残基的磷酸盐损失似乎取决于肽序列中精氨酸或赖氨酸残基的存在。
