Superoxide Dismutases and Catalase

Abstract

Superoxide dismutases (SODs) and catalase represent the primary enzymatic defense against reactive oxygen species. Both enzymes are present in virtually all types of aerobic cells. Both are metalloproteins, employing efficient dismutation reactions to dispose of the two most common reactive oxygen species formed, the superoxide radical anion and hydrogen peroxide. These very fast reactions do not require reducing equivalents and thus energy input. Induction of expression of these enzymes in cell culture and in whole organisms provides protection against deleterious effects of oxidative stress in various situations. Transgenic organisms provided many clues concerning the physiological significance of superoxide dismutases. In the human, mutations of CuZn-superoxide dismutase underly cases of familial amyotrophic sclerosis; pathological aspects of polymorphism of superoxide dismutases have also been extensively studied. Application of the enzymes in therapy and for analysis of the level of reactive oxygen species has been suggested.