Benov Ludmil, Sequeira Fatima
Department of Biochemistry, Faculty of Medicine, Kuwait University, Kuwait.
Redox Rep. 2003;8(6):379-83. doi: 10.1179/135100003225003357.
Iron is among the most important micronutrients used by bacteria. As a partner of the Fenton reaction, however, iron potentiates oxygen toxicity. Strict regulation of iron metabolism, and its coupling with regulation of defenses against oxidative stress, is an essential factor for life in the presence of oxygen. In Escherichia coli, iron metabolism is regulated by the Fur protein. A Fur-deficient mutant, in stationary phase, displayed about 30y-fold lower HPII activity than the respective, Fur-proficient parental strain. Deletion of fur seems to affect HPII catalase specifically, since the mutant was capable of inducing HPI catalase when challenged with H(2)O(2). Low HPII catalase activity appears to be among the reasons for hydrogen peroxide hypersensitivity of the deltafur mutant.
铁是细菌所使用的最重要的微量营养素之一。然而，作为芬顿反应的参与者，铁会增强氧毒性。严格调控铁代谢，并将其与抗氧化应激防御的调控相结合，是在有氧环境中生存的关键因素。在大肠杆菌中，铁代谢由Fur蛋白调控。处于稳定期的Fur缺陷型突变体的HPII活性比相应的Fur功能正常的亲本菌株低约30倍。fur基因的缺失似乎特异性地影响HPII过氧化氢酶，因为该突变体在用H₂O₂刺激时能够诱导HPI过氧化氢酶。低HPII过氧化氢酶活性似乎是Δfur突变体对过氧化氢超敏的原因之一。
