Mitochondria, reactive oxygen species and apoptosis

Mitochondria are involved not only in energy metabolism but also in free radical metabolism. Superoxide anion can be generated through a way of electron leak of respiratory chain and the reactive oxygen species (ROS) can be formed in the further reactions of O-2(radical anion) in mitochondria. The role of mitochondria in antioxidant functions and cell apoptosis is discussed in terms of electron leak of respiratory chain, uncoupling of oxidative phosphorelation, mitochondrial pore, Box- or/and PTP-mediated release of cytochrome c from mitochondria and so on. The signaling act of ROS is emphasized in the regulation of cell apoptosis.