Redox proteomics: From protein modifications to cellular dysfunction and disease

Reactive oxygen and nitrogen species are part of any aerobic lifestyle/metabolism. Low concentrations of selected ROS and RNS are continuously produced inside and outside the cell by a number of pathways, either accidentally or purposefully. Because of the potential toxicity of these reactive species, a number of cellular and extracellular antioxidant defenses, both enzymatic and non-enzymatic, are designed to remove/neutralize ROS, RNS, and RCS directly, to minimize the extent of either their production or damage they can provoke, or to repair oxidative/nitrosative damage caused by them. Due to their high chemical reactivity, ROS and RNS can modify and oxidize various biological molecules, often altering their biological function, such as unsaturated lipids, carbohydrates, nucleic acids, but mostly, because of their high abundance, proteins. These oxidized cellular molecules can cause toxicity as such and/or may degrade to form further toxic products, such as reactive carbonyl species (RCS) generated by peroxidation of polyunsaturated fatty acids (PUFA).