Phosphoproteomics of Cell Lysates Using Titatium Dioxide Phosphopeptide Enrichment Combined With LC-MS/MS

Cellular processes, such as signal transduction, cell division, metabolism, apoptosis, cell motility, and carcinogenesis, are controlled through reversible phosphorylation of proteins. Abnormally phosphorylated proteins have been associated with the pathology of cancer, diabetes, and Alzheimer’s disease. Phosphorylated amino acids exist at a low natural stoichiometry, and require selective enrichment strategies for the concentration of phosphorylated peptides and proteins prior to analysis, usually by mass spectrometry. This case study, from Protea, highlights the use of titanium dioxide (TiO₂) mediated phosphopeptide enrichment for the characterization of phosphoproteins in cell lysates.