DeGnore J P, Qin J
Laboratory of Biophysical Chemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
J Am Soc Mass Spectrom. 1998 Nov;9(11):1175-88. doi: 10.1016/S1044-0305(98)00088-9.
A systematic study of the fragmentation pattern of phosphopeptides in an electrospray (ESI) ion trap mass spectrometer is presented. We show that phosphotyrosine- and phosphothreonine-containing peptides show complicated fragmentation patterns. These phosphopeptides were observed to lose the phosphate moiety in the form of H3PO4 and/or HPO3, but were also detected with no loss of the phosphate group. The tendency to lose the phosphate moiety depends strongly on the charge state. Thus, the highest observed charge state tends to retain the phosphate moiety with extensive fragmentation along the peptide backbone. We also show that phosphoserine-containing peptides have relatively simple fragmentation patterns of losing H3PO4. This loss is independent of the charge state. We suggest strategies for the accurate identification of phosphorylation sites using the ion trap mass spectrometer.
本文介绍了在电喷雾（ESI）离子阱质谱仪中对磷酸肽片段化模式的系统研究。我们发现，含磷酸酪氨酸和磷酸苏氨酸的肽呈现出复杂的片段化模式。观察到这些磷酸肽以H3PO4和/或HPO3的形式失去磷酸部分，但也检测到未失去磷酸基团的情况。失去磷酸部分的倾向在很大程度上取决于电荷状态。因此，观察到的最高电荷状态倾向于保留磷酸部分，并沿肽主链进行广泛的片段化。我们还表明，含磷酸丝氨酸的肽具有相对简单的失去H3PO4的片段化模式。这种损失与电荷状态无关。我们提出了使用离子阱质谱仪准确鉴定磷酸化位点的策略。
