ITRAQ quantitation

Chang, B. Unlti, M. Clauser, K. Carr, S.A. iTRAQ-IT Implementation of iTRAQ quantitation tags on ion trap instruments via MS. Proc. 53rd ASMS Conference on Mass Spectrometry and Allied Topics, San Antonio, Texas, 2005. 

Wu WW, Wang G, Baek SJ et al. Comparative study of three proteomic quantitative methods, DIGE, cICAT, and iTRAQ, using 2D gel- or LC-MALDI TOF/TOF. J Proteome Res 2006 5 651-658. 

L. Zhou, R. Beuerman, A. P. Chew, S. K. Koh, T. Cafaro, E. Urrets-Zavalia, J. Urrets-Zavalia, S. Li, and H. Serra, Quantitative analysis of IV-linked glycoproteins in tear fluid of climatic droplet keratopathy by glycopeptide capture and iTRAQ, J. Proteome Res., 8 (2009) 1992-2003. 

An inherent drawback of this methodology is that quantitative information is only obtained from those peptides which are subjected to MS/MS analysis. This fact stresses the necessity for efficient peptide separation via multidimensional chromatography (e.g., SCX/reversed-phase HPLC) prior to tandem MS analysis. Moreover, ion trap instruments cannot be employed in quantitative iTRAQ experiments since their peptide fragmentation spectra do not contain information... 

It has been demonstrated also that the iTRAQ tandem mass spectrometric quantitative analysis strategy can be used in conjunction with the quadrupole ion trap by performing multiple stages of mass analysis (that is, MS ) [125], For example, chemical derivatization with the iTRAQ reagent not only labels the N-terminus of a peptide, but the lysine side chain also. Thus, tryptic peptides with a modified lysine residue present at the C-terminus will produce a yj product ion at m/z 291 following ClD-tandem mass spectrometry. To generate the low m/z iTRAQ reporter ions required for quantitation, the yj product ion is isolated and subjected to data-dependent CID-MS. Using this approach, peptide identification is achieved in the MS/MS scan, while quantitation is achieved via MS. ... 

Griffin, T.J. Xie, H. Bandhakavi, S. Popko, 1. Mohan, A. Carlis, J.V. Higgins, L. iTRAQ reagent-based quantitative proteomic analysis on a linear ion trap mass spectrometer. J. Proteome Res. 2007, 6, 4200-4209. 

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