Abstract
Ubiquitination is a post-translational modification that affects protein degradation as well as a variety of cellular processes. Methods that globally profile ubiquitination are powerful tools to better understand these processes. Here we describe an updated method for identification and quantification of thousands of sites of ubiquitination from cells, tissues, or other biological materials. The method involves cell lysis and digestion to peptides, immunoaffinity enrichment with an antibody recognizing di-glycine remnants left behind at ubiquitinated lysines, and liquid chromatography-tandem mass spectrometry analysis of the enriched peptides.