Kannan V, Raju P N
Centre for Advanced Study in Botany, University of Madras, Guindy Campus, Chennai 600 025, India.
Indian J Exp Biol. 2002 Sep;40(9):1043-9.
Protection of nitrogenase against oxygen inactivation in diazotrophs involves numerous strategies. Glutathione is known to play an important role in scavenging oxyradicals in many living systems. The involvement of glutathione (reduced) (GSH), glutathione peroxidase (GPX) and glutathione reductase (GR) in the protection of nitrogenase in free living diazotrophs is reported here for the first time. Reduced glutathione content and the activity of glutathione peroxidase and glutathione reductase increased with increase in oxygen concentration under nitrogen fixing conditions but decreased under anaerobic and nitrogenase repressed conditions. This correlation is used to postulate a protecting role for GSH-GPX-GR system against oxygen inactivation of nitrogenase.
固氮生物中固氮酶抵御氧气失活的保护机制涉及多种策略。已知谷胱甘肽在许多生物系统中清除氧自由基方面发挥着重要作用。本文首次报道了还原型谷胱甘肽（GSH）、谷胱甘肽过氧化物酶（GPX）和谷胱甘肽还原酶（GR）在自由生活的固氮生物中对固氮酶的保护作用。在固氮条件下，随着氧气浓度的增加，还原型谷胱甘肽含量以及谷胱甘肽过氧化物酶和谷胱甘肽还原酶的活性升高，但在厌氧和固氮酶受抑制的条件下则降低。这种相关性被用来推测GSH-GPX-GR系统对固氮酶氧气失活具有保护作用。
