Probing Superoxide Dismutases through Radiation Chemistry

AbstractSuperoxide dismutases (SODs) are metalloenzymes that likely evolved to remove superoxide (O2.−) from cells. These enzymes span a range of three uniquely different protein structures and four different metals to enable a similar overall chemistry, the catalytic and accelerated conversion of superoxide to oxygen and hydrogen peroxide. Superoxide dismutases have the attractive feature that the substrate (O2.−) for the catalytic reaction is easily generated using radiation chemistry, allowing the ability to follow catalysis on a fast time scale under a wide variety of conditions. This review will show how the utility of radiation chemistry was realized and enabled mechanistic understanding immediately upon discovery of these enzymes. It will then highlight some applications of pulse radiolysis, carried out in this laboratory, that illustrate mechanistic details of the enzyme function for a variety of wild‐type and mutant superoxide dismutases.