Inner mechanism of protection of mitochondrial electron-transfer proteins against oxidative damage. Focus on hydrogen...

It is generally recognized that the mitochondria are the major source of reactive oxygen species including hydrogen peroxide (H₂O₂). Although the local concentration of H₂O₂ near the electron-transfer chain is potentially quite high, the chain's components are rarely found to be significantly damaged by H₂O₂. Our experimental data, as well as the data published by others, suggest that mitochondrial electron-transfer proteins, which are in the first line to be harmed by ROS, are well prepared to defend themselves. One of such protection mechanism involves peroxidase/catalase-like activity of all major mitochondrial respiration chain players, which catalyze the decomposition of H₂O₂. Understanding the molecular mechanisms, by which mitochondrial electron-transfer proteins might defend themselves against an oxidative stress and therefore being a part of the mitochondrial antioxidant system, can help to clarify many controversial experimental data.