Superoxide dismutases (SOD) convert superoxide to hydrogen peroxide and therefore provide an important ROS defence mechanism. SOD2 is the sole superoxide dismutase in mitochondrial matrix and thus SOD2 knockout mice can be utilized to analyse what effects increased oxidative stress has on mitochondrial proteome. To this end, we purified heart mitochondria from heart Sod2 knockout mice (Sod2 Ckmm cre) and controls and analysed their proteome with label free LS MS/MS.