 defining alterations in signalling pathways in normal and malignant cells is becoming a major field in proteomics . 
 a number of different approaches have been established to isolate , identify and quantify phosphorylated proteins and peptides . in the current report , 
 a comparison between scx prefractionation versus an antibody based approach , both coupled to tio2 enrichment and applied to tmt labelled cellular lysates , is described . 
 the antibody strategy was more complete for enriching phosphopeptides and allowed the identification of a large set of proteins known to be phosphorylated ( 715 protein groups ) with a minimum number of not previously known phosphorylated proteins ( 2 ) . 
Supplementary Material