Preventing Overproduction of Reactive Oxygen Species is a Universal Survival Strategy: Physiological Uncoupling

The highly exergonic reduction of O2 by aerobic organisms yields large amounts of energy. However, the production of toxic partiallyreduced side-reaction products, collectively termed Reactive Oxygen Species(ROS) is a major problem.While ROS detoxification is thoroughly investigated, control of ROS production needs to be analyzed in depth. Uncoupling O2 consumption from ATP synthesis increases electron flow and decreases ROS production. Physiological uncoupling, however, must be tightly controlled to avoid energy depletion and death.

Uncoupling mechanisms include proton sinks, such as mitochondrial permeability transition pores and uncoupling proteins. Protonsinks have not been described in prokaryotes. Instead, prokaryotes, as well as unicellular eukaryotes, arthropods and plants may contain branched respiratory chains.