Detection of proteins containing cysteine residues sensitive to ROS. The membrane proteins labeled with BIAM were subjected to either a 10% SDS-PAGE (left) or a 12% SDS-PAGE (right) and detected by enhanced chemiluminescence (ECL) after blotting with HRP-conjugated streptavidin. Arrows indicate proteins with reduced BIAM labeling in Prx II^–/– mice compared with wild-type mice. Actin was used as an internal control.