Traditional methods for mass spectrometry-based proteomics, such as SILAC (stable isotope labeling with amino acids in cell culture), are insensitive, poorly reproducible, costly, and time consuming. LifeSensors’ TUBEs bind to all polyubiquitin chains with 1-10 nM affinity, overcoming major problems common to mass spectrometry proteomics. LifeSensors has developed K63-, K48-, and M1(linear)-chain selective TUBEs. LifeSensors is actively engaged in developing K6, K11, K29, K27, and K33 polyubiquitin chain-selective TUBEs. The combination of the TUBE-based affinity technology and targeted mass spectrometry is the most powerful way to detect the alternations in PMTs and identify signatures for research and biomarkers. LifeSensors’ ubiquitin proteomics technology can detect ultra-low levels of ubiquitylated biomarkers from tissues and cells.