reactive oxygen species

Reactive oxygen species (ROS) are molecules produced during normal cellular activities, such as cellular respiration. While essential for life, molecular oxygen (O₂) can also be toxic and mutagenic due to its electronic structure, leading to the formation of intermediates like superoxide (O₂⁻) and hydrogen peroxide (H₂O₂). These can further react to form highly potent oxidants like the hydroxyl radical (HO•).1

This process, known as oxidative stress, can damage cellular components, including DNA, and is implicated in aging and various diseases. Organisms have evolved defense systems, such as superoxide dismutases and catalases, to neutralize these harmful ROS. Genetic diseases like chronic granulomatous disease and some forms of amyotrophic lateral sclerosis are linked to defects in these defense mechanisms or the ROS themselves.21