Institut des Biomolécules Max Mousseron, UMR 5247 CNRS-Université Montpellier 1 et 2, Montpellier, France.
Proteomics. 2012 Aug;12(14):2247-57. doi: 10.1002/pmic.201100525.
Sulfation of tyrosine residues is a key posttranslational modification in the regulation of various cellular processes. As such, the detection and localization of tyrosine sulfation is an essential step toward the elucidation of the physiological and pathological roles of this process. Despite substantial advances, intact sulfated peptides are still difficult to detect by MALDI-MS due to the extreme lability of the sulfo-moiety. The present report demonstrates for the first time how intact sulfated peptides can be directly and specifically detected by MALDI-MS in positive reflectron mode by using pyrenemethylguanidine (pmg) as a noncovalent derivatizing agent and an ionization enhancer. This new method allows the determination of the degree of sulfation of sulfopeptides pure or in mixtures. Moreover, the observation of specific peaks in the mass spectra enables a rapid and unambiguous discrimination between phospho- and sulfopeptides.
酪氨酸残基的硫酸化是调节各种细胞过程的关键翻译后修饰。因此，酪氨酸硫酸化的检测和定位是阐明该过程生理和病理作用的重要步骤。尽管取得了很大进展，但由于硫酸酯基的极端不稳定性，完整的硫酸化肽仍然很难通过 MALDI-MS 检测。本报告首次证明了如何使用吡咯烷甲基胍（pmg）作为非共价衍生化试剂和离子增强剂，在正反射模式下通过 MALDI-MS 直接和特异性地检测完整的硫酸化肽。这种新方法允许确定纯硫酸肽或混合物中硫酸肽的硫酸化程度。此外，在质谱中观察到特定的峰，可以快速且明确地区分磷酸化肽和硫酸化肽。
