The SILAC approachOther protocol
For quantitative proteomic studies, our group recently described the SILAC (Stable Isotope Labelling by Amino Acids in Cell Culture) approach.
In this method, independent populations of cells are grown in medium containing different non-radioactive isotope forms of essential amino acids (e.g. arginine and lysine). Because the cells cannot synthesize these amino acids, after some generations all proteins are labelled and therefore can be distinguished and quantified by the mass spectrometer.