Emerit J, Michelson A M
Sem Hop. 1982 Dec 9;58(45):2670-5.
Free radicals have long been well known by physicists but have only interested biologists since 1969 when Fridovich showed that O2 was produced during an enzymatic oxidation. O2 and related radicals are highly toxic. This implies that, in all aerobic cells, mechanisms exist which inactivate free radicals as soon as they are produced by oxidative metabolism. O2 radicals are eliminated by a family of enzymes called superoxide dismutases (SOD). These SOD are present in the cytosol (CuSOD) and in the mitochondria (MnSOD). Overproduction of free radicals, originating in molecular oxygen, may explain the lesions which result from inflammation, ischemia, and radiation exposure. Free radicals can cause damage to membranes, macromolecules, and DNA. Whether free radical production is mainly intracellular or extracellular may determine to a degree which kind of damage will occur.
自由基早已为物理学家所熟知，但自1969年弗里多维奇证明在酶促氧化过程中会产生超氧阴离子以来，才引起生物学家的关注。超氧阴离子及相关自由基具有高毒性。这意味着，在所有需氧细胞中，存在一些机制，能在自由基由氧化代谢产生后立即将其灭活。超氧阴离子自由基可被一类称为超氧化物歧化酶（SOD）的酶清除。这些超氧化物歧化酶存在于细胞质（铜超氧化物歧化酶）和线粒体（锰超氧化物歧化酶）中。源自分子氧的自由基过量产生，可能解释了由炎症、缺血和辐射暴露导致的损伤。自由基可对细胞膜、大分子和DNA造成损害。自由基的产生主要是细胞内还是细胞外，在一定程度上可能决定会发生哪种损伤。
