Redox-optimized ROS balance: a unifying hypothesis.

ABSTRACT: While it is generally accepted that mitochondrial reactive oxygen species (ROS) balance depends on the both rate of single electron reduction of O2 to superoxide (O2.-) by the electron transport chain and the rate of scavenging by intracellular antioxidant pathways, considerable controversy exists regarding the conditions leading to oxidative stress in intact cells versus isolated mitochondria. Here, we postulate that mitochondria have been evolutionarily optimized to maximize energy output while keeping ROS overflow to a minimum by operating in an intermediate redox state. We show that at the extremes of reduction or oxidation of the redox couples involved in electron transport (NADH/NAD+) or ROS scavenging (NADPH/NADP+, GSH/GSSG), respectively, ROS balance is lost. This results in a net

SUBMITTER: Aon MA 

PROVIDER: S-EPMC2891851 | biostudies-literature | 2010 Jun-Jul

REPOSITORIES: biostudies-literature