Oxygen is the quintessential two-edged sword of molecular biology: essential for (animal) life, but at the same time a perennial source of damage to macromolecules. Reactive oxygen species (ROS), arising from both external sources and the intrinsic metabolic machinery of the cell itself, have been implicated in many aspects of cellular aging.
Of particular interest to human beings, especially those living in the rapidly aging post-industrial Western nations, is the relationship between oxidative damage and neurodegenerative illness. While most of the age-related neurodegenerative diseases are caused by accumulation of protein aggregates, it is becoming evident that ROS play an important role in exacerbating the underlying pathologies: e.g., DNA oxidation arises early in the pathogenesis of Alzheimer’s disease; and oxidative damage to a key anti-oxidant defense protein may generate a pernicious positive-feedback loop in the initiating events of Parkinson’s disease.
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