Hassan H M, Fridovich I
Eur J Rheumatol Inflamm. 1981;4(2):160-72.
The univalent reduction of oxygen to the superoxide radical is a commonplace event in biological systems, and the superoxide dismutases, which catalytically scavenge this radical, are the primary defence against its potential cytotoxicity. The superoxide radical and hydrogen peroxide, can interact to generate the hydroxyl radical. Superoxide dismutases are metalloenzymes that can prevent the generation of hydroxyl radical by keeping the level of superoxide radical vanishingly low. Superoxide dismutases are essential for the survival of all oxygen metabolizing organisms. There are three types of superoxide dismutases: the manganese-containing, the iron-containing, and the copper-zinc-containing superoxide dismutases. The copper-zinc containing superoxide dismutases have generally been isolated from eukaryotic cells except for the enzyme from the symbiotic marine bacterium Photobacterium leiogenthi. The copper-zinc containing superoxide dismutases, from different sources, have a molecular weight of about 32,000, are composed of two identical subunits, and contain one atom of copper and one atom of zinc per subunit. The copper participates in the catalytic activity of the enzyme, while the zinc plays only a structural role. The enzyme has been resolved reversibly. Superoxide dismutases have been seen to provide protection against oxygen toxicity, against compounds that cause exacerbation of oxygen toxicity, against ionizing radiation, and also against the damaging sequelae of prolonged inflammation.
在生物系统中，氧单电子还原生成超氧阴离子自由基是常见的现象，而超氧化物歧化酶可催化清除该自由基，是抵御其潜在细胞毒性的主要防线。超氧阴离子自由基和过氧化氢可相互作用生成羟基自由基。超氧化物歧化酶是金属酶，通过将超氧阴离子自由基水平维持在极低水平来防止羟基自由基的生成。超氧化物歧化酶对于所有进行氧代谢的生物的生存至关重要。超氧化物歧化酶有三种类型：含锰超氧化物歧化酶、含铁超氧化物歧化酶和含铜锌超氧化物歧化酶。除了从共生海洋细菌发光杆菌中分离得到的酶外，含铜锌超氧化物歧化酶通常是从真核细胞中分离出来的。不同来源的含铜锌超氧化物歧化酶分子量约为32,000，由两个相同的亚基组成，每个亚基含有一个铜原子和一个锌原子。铜参与酶的催化活性，而锌仅起结构作用。该酶已被可逆地分解。超氧化物歧化酶已被证明可提供保护，抵御氧毒性、抵御导致氧毒性加剧的化合物、抵御电离辐射以及抵御长期炎症的有害后遗症。
