CAT and Alzheimer disease: Mitochondrial dysfunction has also been implicated in AD pathology, Oxidative stress, damage by free radicals in parallel with changes in the expression of superoxide dismutase (SOD) and catalase, both important anti-oxidant enzymes, have been shown in tissue from AD patients (Marcus et al., 1998; Omar et al., 1999; Padurariu et al., 2010).