New Protein Labeling Tools for Mass Spectrometric Analysis from Thermo Fisher Scientific

An expansion of Thermo Fisher Scientific's isobaric tandem mass tags product line now enables protein identification and quantitation through the selective labeling of cysteine-containing peptides from complex biological samples. The new Cysteine-Reactive Tandem Mass Tag (cysTMT) Reagents can be used in multiplex analysis of up to six different samples concurrently in an experiment.

The cysTMT Reagents label only free sulfhydryl groups on cysteine residues, in contrast to the amine-reactive TMT® Reagents. Labeled peptides are then enriched using the Thermo Scientific Immobilized Anti-TMT Antibody Resin. The cysTMT Reagents and Anti-TMT Resin are effective for reducing sample complexity, improving dynamic range and studying cysteine modifications. The cysTMTzero and cysTMTsixplex Reagents are used as isotopic “light” and “heavy” duplex tags for quantitation at the MS stage. These tags enable quantitation of protein expression changes in cell and tissue samples that might not be amenable to metabolic isotopic labeling strategies (e.g., SILAC).