Elucidating the molecular mechanism of TEMPOL-mediated improvement on tolerance under oxidative stress in Saccharomyces cerevisiae. (16th January 2020) - Li, Kai
Graphical abstract: Highlights: TEMPOL improves bioethanol fermentation by yeast under oxidative stress. TEMPOL activates oxidative stress response system prior to H2 O2 addition. TEMPOL eliminates ROS via regulating stress-related genes, enzymes, and cofactors. Abstract: Reactive oxygen species (ROS) appear in universal stress pathways and damage cell components. In this study, 4-hydroxy-2, 2, 6, 6-tetramethylpiperidin-1-oxyl (TEMPOL), a redox-cycling nitroxide and membrane-permeable antioxidant, was investigated for its ability to clear out intracellular ROS induced by hydrogen peroxide (H2 O2 ) shock in Saccharomyces cerevisiae . Cell growth was improved by TEMPOL addition. The mechanism of ROS removal was elucidated by investigating activities of related genes, enzyme, and cofactors. TEMPOL increased the expression of genes involved in oxidative stress response, and enhanced the activities of the superoxide dismutase (SOD) and catalase (CAT) antioxidative proteins. TEMPOL also increased intracellular glutathione (GSH) to remove ROS by supplying more NADPH in cells. Finally, TEMPOL might catalyze the reaction of NADH and ROS due to its dual redox states. Interestingly, the early addition of TEMPOL resulted in a better H2 O2 tolerance, because TEMPOL required time to expand its benefits in different metabolic levels for constructing an enzymatic antioxidant defense system and accumulating non-enzymatic reducing power in advance, akin to a "preventive stimulator".