Szuperoxiddiszmutáz

Szuperoxiddiszmutáz, often abbreviated as SOD, is a group of enzymes that catalyze the dismutation of the superoxide radical (O2•−) into oxygen (O2) and hydrogen peroxide (H2O2). This reaction is a crucial part of cellular defense against oxidative stress, which is caused by the accumulation of reactive oxygen species (ROS). Superoxide is a byproduct of normal aerobic metabolism, particularly within mitochondria during the electron transport chain. If not neutralized, superoxide can damage cellular components like DNA, proteins, and lipids.

There are several forms of SOD, distinguished by their metal cofactors and cellular location. Copper-zinc superoxide dismutase (Cu/Zn-SOD) is found in the cytoplasm and nucleus of most eukaryotic cells. Manganese superoxide dismutase (Mn-SOD) is located in the mitochondria, where a significant amount of superoxide is generated. Extracellular superoxide dismutase (EC-SOD) is found in the extracellular space and plays a role in protecting tissues from externally generated ROS.

The dismutation reaction catalyzed by SOD proceeds in two steps. First, SOD reacts with a superoxide radical to form oxygen and a reduced metal ion. Second, the reduced metal ion reacts with another superoxide radical to regenerate the oxidized metal ion and produce hydrogen peroxide. While hydrogen peroxide is less reactive than superoxide, it can still be damaging and is further detoxified by enzymes like catalase and glutathione peroxidase. SOD enzymes are therefore essential for maintaining cellular homeostasis and preventing the deleterious effects of oxidative damage, which has been implicated in aging and various diseases.