DOI: 10.1002/elps.201800335
The cover picture shows the method for quantitative profiling of the redox status of proteins with maleimide‐polyethylene glycol (m–PEG) tagging. M–PEG has been used to detect oxidized proteins by reacting to the reduced cysteine residues leading to mobility shift in immunoblots; a method called PEG–switch. With PEG–switch, both reduced and oxidized proteins can be observed on the same immunoblot simultaneously, providing a simple quantitative measurement for protein thiol modifications. In this cartoon, proteins with oxidized cysteine residues carry a light backpack which does not hinder the migration of proteins while proteins with reduced cysteine residues would carry heavy PEG backpacks rendering slower migration, depending on the number of PEG backpack. A scoring method is designed to quantitate the extent of cysteine oxidation; lower score means higher extent of oxidation.