スーパーオキシド(O_2^⨪)の反応 : 酸素毒性発現機構解明へのアプローチ

概要

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Superoxide (O_2^⨪) appears to play an important role in various biological processes, such as inflammation, carcinogenesis, radiation-induced damage, aging, phagocytosis and enzyme reactions. O_2^⨪ has been considered to have diverse but not vigorous reactivities compared with other active oxygen species, but has been reported to exert deleterious effects on living cells. Thus, the mechanism of the biological effects of O_2^⨪ has been of great interest. The review reports that O_2^⨪ reacts with some compounds such as acyl halides, polyhalides, or CO_2 to form peroxy intermediates, which have more vigorous reactivities than O_2^⨪ alone. The peroxy intermediates can oxidize olefins or sulfides to the corresponding epoxides or sulfoxides in good yields. The phosphates, also, enhance the reactivity of O_2^⨪ as shown in the base-release reaction from nucleosides induced by O_2^⨪ and the phosphates. These reactions should be important for consideration of the O_2^⨪ toxicity. The reaction mechanisms have been examined in detail using K^<18>O_2 and cyclic voltamography. Furthermore, synergism between O_2^⨪ and CCl_4 has been found in the biological system. Thus, CCl_4 toxicity on Escherichia coli is exacerbated by O_2^⨪. The results obtained should contribute not only to the development of O_2^⨪ for use in organic oxidations, but also to the elucidation of the oxidative reactivity of O_2^⨪ in biological systems.
1988-12-31