Generation of mass tags by the inherent electrochemistry of electrospray for protein mass spectrometry

• Published in: Journal of the American Society for Mass Spectrometry Vol. 15; no. 12; pp. 1767 - 1779
• Main Authors: Roussel, Christophe, Dayon, Loïc, Lion, Niels, Rohner, Tatiana C., Josserand, Jacques, Rossier, Joël S., Jensen, Henrik, Girault, Hubert H.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.12.2004; Springer Nature B.V
• Subjects: Chemical reactions; Computer simulation; Cysteine; Cysteine - analysis; Electrochemical analysis; Electrochemistry; Electrospraying; Fingerprinting; Ions; Marking; Mass spectrometry; Mathematical models; Microchemistry - methods; Peptides; Peptides - chemistry; Proteins; Proteins - chemistry; Reaction kinetics; Residues; Spectrometry, Mass, Electrospray Ionization - instrumentation; Spectrometry, Mass, Electrospray Ionization - methods; Tags
• ISSN: 1044-0305; 1879-1123
• DOI: 10.1016/j.jasms.2004.08.006

We present herein a review of our work on the on-line electrochemical generation of mass tags toward cysteine residues in peptides and proteins. Taking advantage of the inherent electrochemical nature of electrospray generated from a microfabricated microspray emitter, selective probes for cysteine were developed and tested for on-line nonquantitative mass tagging of peptides and proteins. The nonquantitative aspect of the covalent tagging thus allows direct counting of free cysteines in the mass spectrum of a biomolecule through additional adduct peaks. Several substituted hydroquinones were investigated in terms of electrochemical properties, and their usefulness for on-line mass tagging during microspray experiments were assessed with L-cysteine, peptides, and intact proteins. Complementarily, numerical simulations were performed to properly understand the respective roles of mass transport, kinetics of electrochemical-chemical reactions, and design of the microspray emitter in the mass tagging overall efficiency. Finally, the on-line electrochemical tagging of cysteine residues was applied to the analysis of tryptic peptides of purified model proteins for protein identification through peptide mass fingerprinting.