Schellhorn H E, Hassan H M
Department of Microbiology, North Carolina State University, Raleigh 27695-7624.
Can J Microbiol. 1988 Oct;34(10):1171-6. doi: 10.1139/m88-206.
In Escherichia coli, the coordinate action of two antioxidant enzymes, superoxide dismutase and hydroperoxidase (catalase), protect the cell from the deleterious effects of oxyradicals generated during normal aerobic respiration. To evaluate the relative importance of these two classes of enzymes, strains of E. coli deficient in superoxide dismutase and (or) hydroperoxidase were constructed by generalized transduction and their physiological responses to oxygen and oxidant stress examined. Superoxide dismutase was found to be more important than hydroperoxidase in preventing oxygen-dependent growth inhibition and mutagenesis, and in reducing sensitivity to redox-active compounds known to generate the superoxide anion. However, both types of enzymes were required for an effective defense against chemical oxidants that generate superoxide radicals and hydrogen peroxide.
在大肠杆菌中，超氧化物歧化酶和氢过氧化物酶（过氧化氢酶）这两种抗氧化酶的协同作用可保护细胞免受正常有氧呼吸过程中产生的氧自由基的有害影响。为了评估这两类酶的相对重要性，通过广义转导构建了超氧化物歧化酶和（或）氢过氧化物酶缺陷的大肠杆菌菌株，并检测了它们对氧气和氧化应激的生理反应。研究发现，在防止氧气依赖性生长抑制和诱变以及降低对已知能产生超氧阴离子的氧化还原活性化合物的敏感性方面，超氧化物歧化酶比氢过氧化物酶更为重要。然而，对于抵御能产生超氧自由基和过氧化氢的化学氧化剂，这两种酶都是有效防御所必需的。
