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Xanthine oxidase (XO, sometimes 'XAO') is a form of xanthine oxidoreductase, a type of enzyme that generates reactive oxygen species. [ 2 ] These enzymes catalyze the oxidation of hypoxanthine to xanthine and can further catalyze the oxidation of xanthine to uric acid. These enzymes play an important role in the catabolism of purines in some ...
In chemistry and biology, reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen (O2), water, and hydrogen peroxide. Some prominent ROS are hydroperoxide (O 2 H), superoxide (O 2-), [ 1 ] hydroxyl radical (OH.), and singlet oxygen. [ 2 ] ROS are pervasive because they are readily produced from O 2, which is ...
The oxygen reduction reaction is an essential reaction for aerobic organisms. Such organisms are powered by the heat of combustion of fuel (food) by O 2. Rather than combustion, organisms rely on elaborate sequences of electron-transfer reactions, often coupled to proton transfer. The direct reaction of O 2 with fuel is precluded by the oxygen ...
Oxygen evolution. Oxygen evolution is the process of generating molecular oxygen (O 2) by a chemical reaction, usually from water. Oxygen evolution from water is effected by oxygenic photosynthesis, electrolysis of water, and thermal decomposition of various oxides. The biological process supports aerobic life.
Respiratory burst(or oxidative burst) is the rapid release of the reactive oxygen species(ROS), superoxide anion(O−. 2) and hydrogen peroxide(H. 2O. 2), from different celltypes. This is usually utilised for mammalian immunological defence, but also plays a role in cell signalling.
An oxyanion, or oxoanion, is an ion with the generic formula AxOz−y (where A represents a chemical element and O represents an oxygen atom). Oxyanions are formed by a large majority of the chemical elements. [ 1 ] The formulae of simple oxyanions are determined by the octet rule. The corresponding oxyacid of an oxyanion is the compound HzAxOy ...
Original reactions reported by Baeyer and Villiger. There were three suggested reaction mechanisms of the Baeyer–Villiger oxidation that seemed to fit with observed reaction outcomes. [16] These three reaction mechanisms can really be split into two pathways of peroxyacid attack – on either the oxygen or the carbon of the carbonyl group. [17]
There are three known stable isotopes of oxygen (8 O): 16O, 17O, and 18O. Radioactive isotopes ranging from 11O to 28O have also been characterized, all short-lived. The longest-lived radioisotope is 15O with a half-life of 122.266 (43) s, while the shortest-lived isotope is the unbound 11O with a half-life of 198 (12) yoctoseconds, though half ...