biostudies-literatureOrdureau ANHGRI NIH HHSNINDS NIH HHSNational Institutes of HealthNIGMS NIH HHS3009-3013https://www.ebi.ac.uk/biostudies/studies/S-EPMC8210946biostudies-literatureUnknown20(5)Stable isotope labeling is a leading strategy for mass-spectrometry-based peptide quantification. Whereas TMTpro isobaric tagging can quantify up to 16 multiplexed samples in a single experiment, nonisobaric, yet chromatographically indistinguishable, variants of TMTpro reagents can be used in conjunction with the isobaric tag series for various peptide-targeting applications. Here we test the performance of two nonisobaric TMTpro variants, a stable-isotope-free TMTproZero tag and a nearly fully isotope-labeled "super-heavy" variant, shTMTpro, in a targeted assay for peptides of charge state 4+. We label each peptide with TMTproZero or Super Heavy TMTpro reagents and separately spike each peptide into a TMTpro16-labeled background (equal amount of peptide across all 16 channels). We observJournal of proteome researchSuper Heavy TMTpro Labeling Reagent: An Alternative and Higher-Charge-State-Amenable Stable-Isotope-Labeled TMTpro Variant.PMC8210946NS083524-11R01 GM132129U24 HG006673GM67945R01 NS083524GM132129R37 NS083524HG006673-07U41 HG006673R01 GM067945Harper JWPaulo JAYu QRogers JCGygi SPOrdureau ABomgarden RDfalseSuper Heavy TMTpro Labeling Reagent: An Alternative and Higher-Charge-State-Amenable Stable-Isotope-Labeled TMTpro Variant.Stable isotope labeling is a leading strategy for mass-spectrometry-based peptide quantification. Whereas TMTpro isobaric tagging can quantify up to 16 multiplexed samples in a single experiment, nonisobaric, yet chromatographically indistinguishable, variants of TMTpro reagents can be used in conjunction with the isobaric tag series for various peptide-targeting applications. Here we test the performance of two nonisobaric TMTpro variants, a stable-isotope-free TMTproZero tag and a nearly fully isotope-labeled "super-heavy" variant, shTMTpro, in a targeted assay for peptides of charge state 4+. We label each peptide with TMTproZero or Super Heavy TMTpro reagents and separately spike each peptide into a TMTpro16-labeled background (equal amount of peptide across all 16 channels). We observ2021-01-01T00:00:00Z2021 May2025-04-05T14:05:41.26Z2025-04-05T14:05:41.26ZS-EPMC82109463368936510.1021/acs.jproteome.0c01056