Electrochemical cleavage of peptide bonds for mass spectrometry-based proteomics

Electrochemical protein oxidation is emerging as an instrumental alternative to chemical and enzymatic cleavage in MS-based proteomics and as a powerful tool to study oxidation of peptides and proteins in vitro. The main drawbacks of electrochemical peptide cleavage is the comparatively low cleavage yield and the increased complexity of reaction mixtures due to the generation of non-cleavage oxidation products.
The theme of this thesis is to develop new methods on the basis of electrochemistry combined with mass spectrometry (EC-MS) to improve electrochemical protein cleavage and its application in MS-based proteomics combined with the tagging of electrochemically-generated reactive intermediates. We have developed improved methods for peptide and protein cleavage, including miniaturization and improved cell configuration with boron doped diamond (BDD) electrodes in collaboration with colleagues from Twente University. An efficient and selective labeling and capturing strategy for the cleaved peptides of interest based on specific reactions with the spirolactone moieties has been established to decrease sample complexity and boost proteomics analysis efficiency after electrochemical protein digestion.
The second aim of this thesis is to check the feasibility of using electrochemical oxidation in vitro to mimic in vivo oxidative reactions of peptides and proteins and to study oxidation mechanisms. Product studies of Gly-Met-Gly generated by radiolytic and electrochemical oxidation were performed in collaboration with colleagues from the University of Bologna (ISOF), Italy.