300089 PP Pro- and antioxidative metabolites in plants - function and detection (2011S)

Nearly all metabolites of a living organisms are affected by redox-chemical reactions. In this context, reactive oxygen species (ROS), such as superoxide anion radical or hydrogen peroxide, are formed. ROS are important signal molecules in the cell, but too high concentrations cause oxidative stress. Here, transition metals, such as iron or copper, are important catalysts of hydroxyl radical (•OH) formation (Fenton reaction). Antioxidative compounds (e.g. ascorbic acid) are important radical scavengers but, depending on the reaction milieu, the identical molecule may also cause pro-oxidative effects. The antioxidative apparatus contributes to general stress tolerance. Demonstrations will include Arabidopsis as model organism.