Oxygen Radicals and Cancer: Free Radical Generation and Oxidative Damage in Mitochondria

摘要

Evidence is increasing that oxygen toxicity, through the formation of reactive oxygen radicals, plays a role in carcinogenesis and, possibly, aging. Mitochondria consume the bulk of cellular oxygen in a process that involves a series of electron transfer catalysts, which can potentially autooxidize with the release of superoxide radicals. We describe detection schemes for mitochondrial radicals, which are being developed with ESR spin probe techniques, and which are designed to elucidate the pathways of oxidative damage. We also consider the activities of mitochondrial electron transport and isolated electron transport complexes in superoxide radical generation, transition metal catalysis of free radical formation and evidence for the formation of thiyl radicals and their possible involvement in oxidative damage. We conclude with a comprehensive hypothesis for the production and fate of mitochondrial oxygen radicals. 40 refs., 3 figs. (ERA citation 10:052474)