Trimethylation Enhancement Using Diazomethane (TrEnDi): A Novel Technique to Enhance the Sensitivity of MS-Based Analyses of Biological Molecules

Defining cellular processes relies heavily on elucidating the temporal dynamics of both lipids and proteins. Different mass spectrometry (MS)-based quantitative strategies have emerged to map protein and lipid dynamics over the course of stimuli. We report the development of a novel MS-based quantitative proteomics and lipidomics strategy with unique analytical characteristics. By reacting with diazomethane, analytes are modified to contain fixed, permanent positive charges resulting in improved ionization characteristics and predictable dissociation pathways. Optimization and determination of reactive functional groups enabled a priori prediction of MS2 fragmentation patterns for both modified peptides and lipids. The strategy was tested on digested BSA and successfully quantified a peptide not observable prior to modification. Our chemistry eliminates the need for protonation during ionization, reduces ion suppression, and permits predictable MRM-based or precursor ion-based quantitation with improved sensitivity.