iodoTMTsixplex™ Isobaric Label Reagents and Kits

Thermo Scientific iodoTMT Label reagents enable multiplexed identification and quantitation of cysteine containing peptides in different samples using tandem mass spectrometry. IodoTMT reagents are sets of isobaric (mass and structure) isomers that are iodoacetyl-activated for covalent, irreversible labeling of sulfhydryl (–SH) groups. iodoTMTzero Label Reagent allows testing and optimization of sample preparation, labeling, fractionation, and MS fragmentation for peptide identification and reporter detection without using the more costly isotope-labeled compounds.

Iodoacetyl tandem mass tag reagents enable selective labeling of cysteine-containing peptides for multiplexed sample quantitation using LC-MS/MS analysis. Similar to iodoacetamide, iodoTMT reagents react specifically with reduced cysteines (Cys) in peptides and proteins and enable quantitation of the relative abundance of cysteine modifications, such as S-nitrosylation and the oxidation of disulfide bonds. IodoTMT reagents irreversibly label free sulfhydryl groups on cysteine residues, in contrast to previous reversible cysteine-reactive TMT (cysTMT) reagents.

To selectively analyze the cysteine-labeled peptides, the sample may be enriched using Immobilized Anti-TMT Antibody Resin (Cat. No. 90076) and TMT Elution Buffer (Cat. No. 90104). This approach of selective thiol-labeling and affinity enrichment is similar to isotope-coded affinity tags (ICAT method) but allows for affinity enrichment with a non-biological tag and higher multiplex quantitation.

Features of iodoTMT reagents
• Specific—only reacts with sulfhydryl groups (reduced, unmodified cysteine residues)
• Irreversible—labeled proteins and peptides are not susceptible to reducing agents
• Flexible—options for duplex isotopic (MS) or sixplex isobaric (MS/MS) quantitation
• Versatile—can be used to study cysteine modifications (e.g., di-sulfide bridges, S-nitrosylation)