diGly
diGly, in proteomics, refers to the diglycine remnant that remains on a lysine residue of a substrate protein after trypsin digestion in ubiquitin-like modification workflows. Ubiquitination involves attaching ubiquitin to lysine side chains through an isopeptide bond. When samples are proteolytically digested with trypsin, most of the ubiquitin is removed, but the C-terminal glycine residues of ubiquitin leave behind a di-glycine tag on the modified lysine. This diGly tag serves as a molecular signature indicating that the lysine was previously ubiquitinated.
In practice, diGly is detected by targeted mass spectrometry workflows. The presence of the diGly remnant produces
diGly-based proteomics has become a foundational approach for characterizing the ubiquitylome, aiding investigations into protein stability,
Limitations include the potential for misassignment due to other ubiquitin-like modifiers that can leave similar remnants,