1991 年 39 巻 5 号 p. 1352-1354
The superoxide (O2-·) production in Escherichia coli through the action of benzofurazans (BZs) was examined using the cytochrome c (cyt. c) reduction method. Adding BZs to E. coli cell suspensions caused the cyt. c reduction, which was completely inhibited by superoxide dismutase (SOD). The effects of BZs on cyt. c reduction was in the order of benzofurazan (1) ≈ 4, 7-dimethylbenzofurazan (2) ≈ 4, 7-dibromobenzofurazan (3) < 4-bromo-6-cyanobenzofurazan (4) < 4, 7-dicyanobenzofurazan (5). This was correlated with the toxicity of BZs against E. coli growth (1 ≈ 2 ≈ 3 < 4 < 5) and with the redox potentials of BZs (1 ≈ 2 < 3 < 4 < 5). The formation of compound 5 anion radical in the cell suspensions in the absence of dioxygen (O2), was determined using ESR spectrum. The ESR signal of the anion radical disappeared with the addition of O2. The BZs effected the O2-· production in E. coli cells.
