Oxidative Stress, Protein Damage
Most cells in the body derive energy through the mitochondrial oxidative phosphorylation wherein molecular oxygen is ultimately reduced to water. A small percentage of oxygen escapes this pathway and transforms into toxic and labile reactive oxygen species (ROS) [namely, superoxide (O2.−), hydrogen peroxide (H2O2), and hydroxyl radical (OH.)]. Generation of ROS is a continuous physiological process implicated in immune function and cell signaling.
Nature has evolved antioxidant molecules (e.g., GSH), antioxidant enzymes (e.g., Catalase, glutathione peroxidase), and repair enzymes to detoxify ROS thereby maintaining a reduced intracellular environment. When there is an increased ROS or decreased cellular antioxidants or both, such a condition is termed as “oxidative stress.” Oxidative stress targets biomolecules and causes DNA oxidation, protein oxidation and aggregation, lipid peroxidation, etc., ultimately triggering cell death. Brain is comparatively more susceptible to...
- Danielson SR, Andersen JK (2008) Oxidative and nitrative protein modifications in PD. Free Radic Biol Med 44:787–794Google Scholar