Signaling Functions of Reactive Oxygen Species

Abstract

We review signaling by reactive oxygen species, which is emerging as a major physiological process. However, among the reactive oxygen species, H2O2 best fulfills the requirements of being a second messenger. Its enzymatic production and degradation, along with the requirements for the oxidation of thiols by H2O2, provide the specificity for time and place that are required in signaling. Both thermodynamic and kinetic considerations suggest that among possible oxidation states of cysteine, formation of sulfeni…