The combination of cysteine-specific modifiers, iodoacetanilide (IAA) and (13)C7-labelled iodoacetanilide ((13)C7-IAA), has been applied to absolute quantification of proteins. The selected reaction monitoring (SRM) with the use of nano liquid chromatography/nanoelectrospray ionisation ion trap mass spectrometry (nano LC/nano-ESI-IT-MS) analysis was applied to precise quantification of three commercial proteins. Good correlation was observed between the theoretical ratios and observed ratios for all these proteins both in a simple buffer solution and in a complex protein environment. Due to efficient tagging, this method does not require separate synthesis of isotope-labelled peptides for the SRM studies. The authors concluded that this method is expected to be a useful tool for proteomics research.
Authors: Kurono S, Kaneko Y, Matsuura S, Niwayama S. ;Full Source: Bioorganic & Medicinal Chemistry Letters. 2015 Mar 1;25(5):1110-6. doi: 10.1016/j.bmcl.2014.12.090. Epub 2015 Jan 7. ;