reactive oxygen species (ROS)

Molecules including peroxides, hydroxyl radicals, and superoxide may oxidatively damage proteins. Many selenoproteins are able to decompose or reduce ROS. While the traditional view is that selenoproteins thus protect cellular structures from oxidative damage, a more modern view stresses the signaling roles of ROS and oxidatively modified proteins. Selenoproteins may thus contribute to regulation of cellular
physiology in addition to a “protective” role against oxidative damage.