Synthesis and proteomic activity evaluation of a new isotope-coded affinity tagging (ICAT) reagent

During recent years, quantitative proteome profiling has taken advantage of incorporating the traditional stable isotope dilution analysis into global scale or discovery-based proteomic experiments that use mass spectrometers as detectors to allow the pairwise study of differently expressed proteins. Quantitative protein analysis by means of the isotope-coded affinity tag (ICAT) method and tandem mass spectrometry (MS) enables the pairwise comparison of protein expression levels in biological samples. Herein, a modified ICAT reagent, named BAA-ICAT (beta-alanine-arm-ICAT) in which the polyether linker is replaced by a more water-soluble polyamide one, was investigated.