Protein phosphorylation is recognized as a fundamental process which regulates cell differentiation, growth, and migration. Analyzing protein phosphorylation is complicated by the low concentration of any given phosphoprotein and any one time, and the relatively low ionization efficiency of phosphopeptides in MS analysis. Therefore, enrichment of phosphopeptides and the relative reduction of non-phosphorylated peptides is critical to accurate analysis of protein digests by LC/MS.
GL Sciences’ Titanium Dioxide (TiO2 or Titania) products have emerged as the most effect means of phosphopeptide enrichment of protein digests prior to LC/MS analysis, replacing IMAC as the primary means of phosphopeptide sample pretreatment. Enrichment by titanium dioxide and IMAC, remain, however, complimentary techniques and are often used in combination to obtain optimal phosphopeptide analysis.