The Redox System in C. elegans, a Phylogenetic Approach

Figure 1

Simplified pathways of ROS production and antioxidant detoxification in a C. elegans cell. ROS molecules superoxide (O_2•−), hydrogen peroxide (H₂O₂), and hydroxyl radical (^•OH) are depicted in red. Antioxidants convert ROS to less reactive molecules. The five different superoxide dismutase enzymes convert superoxide to H₂O₂ and are depicted in their respective cellular compartments. Catalase, peroxiredoxin (Prx), and glutathione peroxidase (Gpx) convert H₂O₂ to H₂O and O₂. Rapid detoxification of H₂O₂ is necessary as it can become oxidised to form the potent free-radical ^•OH. ROS can be damaging to DNA, RNA, proteins, and lipids, and high ROS levels can cause oxidative stress. Some antioxidant genes, such as catalase and sod-3, can be upregulated in response to oxidative stress.