Quantitative Proteome Analysis Using Isobaric Peptide Termini Labeling (IPTL)
The quantitative comparison of proteome level changes across biological samples has become an essential feature in proteomics that remains challenging. We have recently introduced isobaric peptide termini labeling (IPTL), a novel strategy for isobaric quantification based on the derivatization of peptide termini with complementary isotopically labeled reagents. Unlike non-isobaric quantification methods, sample complexity at the MS level is not increased, providing improved sensitivity and protein coverage. The distinguishing feature of IPTL when comparing it to more established isobaric labeling methods (iTRAQ and TMT) is the presence of quantification signatures in all sequence-determining ions in MS/MS spectra, not only in the low mass reporter ion region. This makes IPTL a quantification method that is accessible to mass spectrometers with limited capabilities in the low mass range. Also, the presence of several quantification points in each MS/MS spectrum increases the robustness of the quantification procedure.
Key wordsChemical labeling isobaric labeling IsobariQ IPTL iTRAQ mass spectrometry quantitative proteomics TMT
IPTL was supported by the National Program for Research in Functional Genomics in Norway (FUGE, project no. 183418/S10) of the Norwegian Research Council, MLSUiO and FUGE-Øst to BT.
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