Isotope Coded Protein Labelling (ICPL) in combination with Liquid Chromatography MALDI-TOF/TOF mass spectrometry analysis (LC-MALDI) used for the quantification of complex protein mixtures

摘要

Quantification of protein expression levels in complex protein mixtures like cell lysates or tissue extracts is still a challenge in proteomics. This is particularly the case when low amounts of proteins are available or the protein mixture contains mainly membrane proteins, such that 2D gel electrophoresis in combination with fluorescence dye labeling would be unable to be used for quantification [1-6]. In this case, isotopic labeling in conjunction with Liquid Chromatography and mass spectrometry is the method of choice. Here we have validated a method utilizing an Isotope Coded Protein Label (ICPL) reagent with Liquid Chromatography and mass spectrometry (LC-MALDI) for the quantification of protein expression levels in complex protein mixtures.