Figure 3

Pros and cons of the most useful phosphoproteomic -MS based tools. Generally, immunoprecipitation of Tyrosine via antibodies, is more efficient than antibody immunoprecipitation of Serine and Threonine residues. On the other hand, affinity chromatography of IMAC and TiO₂, is more efficient for isolating phosphorylated residues of Serine and Threonine than Tyrosine. Moreover, TiO₂ has shown higher specificity when it is coupled to DHB than IMAC. In addition, IMAC has shown higher specificity when converting non-phosphorylated residues (acidic peptides) to methyl esters, but the complexity of spectra increases. Furthermore, SCX, SAX and calcium phosphate precipitation methods, are more efficient when coupled to IMAC and/or TiO₂ for clinical phosphoproteomic studies.