Reactive Oxygen Species

**Definition:** Molecules or ions formed by the incomplete one-electron reduction of oxygen. These reactive oxygen intermediates include SINGLET OXYGEN; SUPEROXIDES; PEROXIDES; HYDROXYL RADICAL; and HYPOCHLOROUS ACID. They contribute to the microbicidal activity of PHAGOCYTES, regulation of SIGNAL TRANSDUCTION and GENE EXPRESSION, and the oxidative damage to NUCLEIC ACIDS; PROTEINS; and LIPIDS.

**Tree numbers:** - D01.339.431 - D01.650.775 - D02.389.593

**Synonyms:** - Oxygen Radical - Active Oxygen Species - Reactive Oxygen Intermediates - Pro-Oxidants - Oxygen Species, Reactive - Oxygen Radicals - Pro-Oxidant - Active Oxygen