Oxidative stress, antioxidants, and chemoprevention: On the role of oxidant-induced signaling in cellular adaptation

Abstract

Reduction/oxidation (redox) processes are at the center of aerobic metabolism. The metabolic generation of molecules with energy-rich bonds that are to be used for biosynthetic purposes requires molecular oxygen, which serves as the ultimate oxidant and electron acceptor, thereby driving numerous redox reactions, including those that are part of the respiratory chain located at the inner mitochondrial membrane. Macronutrient ('fuel') catabolism provides electrons in the form of carrier molecules such as NADH or FADH 2 that are reoxidized at the inner mitochondrial membrane, feeding the electron flow along the respiratory chain of protein complexes all the way to molecular oxygen. This flow then drives the build-up of a proton gradient across the inner mitochondrial membrane that is exploited to generate adenosine triphosphate (ATP), the universal energy currency of the living cell that is required for metabolism.