A Quantitative Chemical Proteomics Approach for Site-specific Stoichiometry Analysis of Ubiquitination

Yunan Li, Jonathan Evers, Ang Luo, Luke Erber, Zachary Postler, Yue Chen

Research output: Contribution to journalArticle

4 Scopus citations


Stoichiometric analysis of post-translational modifications is an emerging strategy for absolute quantification of the fractional abundance of the modification. Herein, a quantitative chemical proteomic workflow for stoichiometric analysis of ubiquitination is reported, named isotopically balanced quantification of ubiquitination (IBAQ-Ub). The strategy utilizes a new amine-reactive chemical tag (AcGG-NHS) that is structurally homologous to the GG remnant of ubiquitin on modified lysine after trypsin cleavage and therefore enables the generation of structurally identical peptides from ubiquitinated and unmodified lysine residues following trypsin digestion and secondary stable isotopic labeling. The strategy is highly robust, sensitive, and accurate with a wide dynamic range using either protein standards or complex cell lysates. Thus, this work provides an efficient chemical proteomics tool for quantitative stoichiometric analysis of ubiquitination signaling pathways.

Original languageEnglish (US)
Pages (from-to)537-541
Number of pages5
JournalAngewandte Chemie - International Edition
Issue number2
StatePublished - Jan 8 2019



  • IBAQ-Ub
  • proteasome inhibition
  • quantitative proteomics
  • stoichiometry
  • ubiquitination

PubMed: MeSH publication types

  • Journal Article
  • Research Support, U.S. Gov't, Non-P.H.S.

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