<prompt> Which of the following enzyme protects the brain from free radical injury?HydroxylaseMyeloperoxidaseSuperoxide dismutaseMono Amine Oxidase  <response>: There are several cellular mechanisms by which cells remove free radicals and thereby protect organs from injury. Superoxide is a free radical, it is inactivated by superoxide dismutase SOD and is conveed into hydrogen peroxide. There are two types of superoxide dismutases such as manganese SOD located in the mitochondria and copper zinc SOD located in the cytosol. Ref: Robbins Pathologic Basis of Diseases, 5th Edition, Page 12-13 