Retro Diels-Alder Fragmentation of Fulvene-Maleimide Bioconjugates for Mass Spectrometric Detection of Biomolecules

Katherine G. Stevens, Lewis O. McFarlane, Kirsten Platts, Neil O’Brien-Simpson, Wenyi Li, Anton Blencowe, Paul J. Trim, Tara L. Pukala

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1 Citation (Scopus)


Diels-Alder chemistry is a well-explored avenue for the synthesis of bioactive materials; however, its potential applications have recently expanded following the development of reactions that can be performed in buffered aqueous environments at low temperatures, including fulvene-maleimide [4 + 2] cycloadditions. In this study, we synthesized two novel amine-reactive fulvene linkers to demonstrate the application of this chemistry for generating mass spectrometry-cleavable labels (“mass tags”), which can be used for the labeling and detection of proteins. Successful conjugation of these linkers to maleimide-labeled peptides was observed at low temperatures in phosphate-buffered saline, allowing the non-destructive modification of proteins with such mass tags. The labile nature of fulvene-maleimide adducts in the gas phase also makes them suitable for both matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) mass spectrometric analysis. Unlike previous examples of MALDI mass tags, we show that fulvene-maleimide cycloaddition adducts fragment predictably upon gas-phase activation without the need for bulky photocleavable groups. Further exploration of this chemistry could therefore lead to new approaches for mass spectrometry-based bioassays.

Original languageEnglish
Pages (from-to)12204-12212
Number of pages9
JournalAnalytical Chemistry
Issue number36
Publication statusPublished or Issued - 14 Sep 2021

ASJC Scopus subject areas

  • Analytical Chemistry

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