These protein extracts provide ideal model systems for development and optimization of various sample prep methods, including isobaric tagging and enrichment.
In the example of isobaric tagging shown here, three aliquots of the human K562 predigested extract were labeled with three different TMT isobaric mass tag reagents (TMT126, TMT127 and TMT128) and mixed at a 10:5:1 ratio. Relative quantitative ratio between the mass tags was determined with an LTQ Orbitrap Velos Pro™ mass spectrometer. The data show good correlation between the expected and observed protein quantitation levels.