An alkyl hydroperoxide reductase from Salmonella typhimurium involved in the defense of DNA against oxidative damage. Purification and properties.
An alkyl hydroperoxide reductase from Salmonella typhimurium involved in the defense of DNA against oxidative damage. Purification and properties.
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DOI：
10.1016/s0021-9258(18)94214-6
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发表时间：
1989-01
期刊：
影响因子：
--
通讯作者：
Fredric S. Jacobson;Robin;Morgan;Michael;Christmanlf;Bruce;Amesll
中科院分区：
文献类型：
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作者：
Fredric S. Jacobson;Robin;Morgan;Michael;Christmanlf;Bruce;Amesll
在鼠伤寒沙门氏菌和大肠杆菌中都发现了一种过氧化物还原酶（过氧化物酶），它可以利用NADH或NADPH作为还原剂，将脂质氢过氧化物和其他烷基氢过氧化物转化为相应的醇类。这种酶显示出在防止烷基过氧化氢诱变中起作用。据我们所知，这项工作代表了肠道细菌中NAD（P）H过氧化物酶的首次描述，也是首次报道的对烷基氢过氧化物表现出高活性的细菌过氧化物酶。建立了一种基于高效液相色谱的烷基过氧化氢还原酶测定方法，通过监测过氧化氢异丙苯（一种模型烷基过氧化氢）的还原过程。通过使用该测定，已经从aS中纯化了酶。typhimurium调节突变体，oxyR 1，其过表达参与防御氧化损伤的许多蛋白质，并且其含有比野生型菌株多20倍的烷基氢过氧化物还原酶。纯化的活性需要存在具有22，000和57，000的亚基分子量的两种可分离组分。57-kDa蛋白质含有结合的FAD辅因子，并且当与22-kDa蛋白质结合时，可以使用NADH或NADPH作为电子供体用于直接还原氧化还原染料或烷基氢过氧化物。因此，这种酶可以作为原核生物中的谷胱甘肽还原酶/谷胱甘肽过氧化物酶系统的等价物。
A peroxide reductase (peroxidase) which converts lipid hydroperoxides and other alkyl hydroperoxides to the corresponding alcohols, using either NADH or NADPH as the reducing agent, has been identified in bothSalmonella typhimuriumandEscherichia coli. This enzyme is shown to play a role in protecting against alkyl hydroperoxide mutagenesis. To our knowledge this work represents the first description of an NAD(P)H peroxidase in enteric bacteria and the first reported bacterial peroxidase to exhibit high activity toward alkyl hydroperoxides. A high performance liquid chromatography-based assay for the alkyl hydroperoxide reductase has been developed by monitoring the reduction of cumene hydroperoxide, a model alkyl hydroperoxide. By using this assay, the enzyme has been purified from aS. typhimuriumregulatory mutant,oxyR1, which overexpresses a number of proteins involved in defenses against oxidative damage, and which contains 20-fold more of the alkyl hydroperoxide reductase than the wild-type strain. The purified activity requires the presence of two separable components having subunit molecular weights of 22,000 and 57,000. The 57-kDa protein contains a bound FAD cofactor and can use either NADH or NADPH as an electron donor for the direct reduction of redox dyes, or of alkyl hydroperoxides when combined with the 22-kDa protein. This enzyme may thus serve as a prokaryotic equivalent to the glutathione reductase/glutathione peroxidase system in eukaryotes.