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In chemistry, a superoxide is a compound that contains the superoxide ion, which has the chemical formula O − 2. [1] The systematic name of the anion is dioxide(1−).The reactive oxygen ion superoxide is particularly important as the product of the one-electron reduction of dioxygen O 2, which occurs widely in nature. [2]
Superoxide dismutase (SOD, EC 1.15.1.1) is an enzyme that alternately catalyzes the dismutation (or partitioning) of the superoxide (O − 2) anion radical into normal molecular oxygen (O 2) and hydrogen peroxide (H 2 O 2). Superoxide is produced as a by-product of oxygen metabolism and, if not regulated, causes many types of cell damage. [2]
superoxide (O − 2) is produced by reduction of O 2. [4] Several grams are produced per day in the human body within the mitochondria. [5] O 2 + e − → O − 2. Competing with its formation, superoxide is destroyed by the action of superoxide dismutases, enzymes that catalyze its disproportionation: 2 O − 2 + 2H + → O 2 + H 2 O 2
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Superoxides are a class of compounds that are very similar to peroxides, but with just one unpaired electron for each pair of oxygen atoms (O − 2). [6] These compounds form by oxidation of alkali metals with larger ionic radii (K, Rb, Cs). For example, potassium superoxide (KO 2) is an orange-yellow solid formed when potassium reacts with oxygen.
An archaeological site in Ethiopia has revealed that a population of humans survived the eruption of Sumatra’s Mount Toba 74,000 years ago. One of the largest eruptions in Earth’s history ...
The superoxide anion, • O − 2, and the hydroperoxyl radical exist in equilibrium in aqueous solution: • O − 2 + H 2 O ⇌ HO • 2 + HO −. The pK a of HO 2 is 4.88. Therefore, about 0.3% of any superoxide present in the cytosol of a typical cell is in the protonated form. [4] It oxidizes nitric oxide to nitrogen dioxide: [2] • NO ...
Bone fragments unearthed in a cave in central Germany show that our species ventured into Europe's cold higher latitudes more than 45,000 years ago - much earlier than previously known - in a ...