Novel biomarkers of protein oxidation sites and degrees using horse cytochrome c as the target by mass spectrometry

► New biomarker pipeline for cytochrome c oxidation is established based on LC and MS. ► Residues sensitive to oxidative stress are located at Cys14, Cys17, Met65 and Met80. ► Oxidation to these sites is controlled by residue type and residue location. ► Dose-effect experiments verify they are valid biomarkers for cytochrome c oxidation.