Tandem Mass Tag Technology

Isobaric chemical tags are powerful tools that enable concurrent identification and quantitation of proteins in different samples using tandem mass spectrometry. They are small chemical molecules with identical structure that covalently attach to the free amino termini of lysine residues of peptides and proteins, thereby labeling various peptides in a given sample. During the MS/MS analysis, each isobaric tag produces a unique reporter ion signature that makes quantitation possible. In the first MS analysis, the labeled peptides are indistinguishable from each other; however, in the tandem MS mode during which peptides are isolated and fragmented, each tag generates a unique reporter ion. Protein quantitation is then accomplished by comparing the intensities of the six reporter ions in the MS/MS spectra.

Thermo Scientific Tandem Mass Tags (TMT)   are uniquely designed to enable a rapid and cost-effective transition from method development to high-throughput protein quantitation. The tags consist of TMT0 (zero), the TMT² two-plex set and the TMT⁶ six-plex set. The TMT0 tag 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. The TMT² reagent set allows two-plex protein profiling for small studies. The TMT⁶ reagent set allows six-plex protein profiling for multiple conditions, including time courses, dose responses, replicates or multiple sample comparisons. Each TMT tag is based on the same chemical structure, eliminating the need to modify labeling conditions or HPLC separation conditions between experiments.