An overview of the qualitative analysis of phosphoproteins by mass spectrometry.

Protein phosphorylation is a reversible and frequently occurring posttranslational modification regulating a large number of biological functions. Understanding the role phosphorylation events play in biochemical pathways requires the detection of phosphorylated proteins and their phosphorylated amino acids. Mass spectrometry has developed as the premier method for characterizing phosphoproteins as it is sensitive to detecting phosphosites within a single protein or a complex protein mixture (phosphoproteomics). Here an overview is provided of the sample separation and mass spectrometry techniques commonly used for qualitative phosphoprotein analysis.