CAT and ischemia: demonstrated a higher concentration of selenoprotein T in rat cardiac tissues after ischemia; this protein rendered cardioprotection by inhibiting oxidative stress.[121] The GPx enzymes are more competitive in ROS clearance than SOD or CAT.[122] They degrade H2O2 and lipid hydroperoxide, the product of lipid peroxidation.[123] Four GPx isoforms have been identified so far.