Koháryová M, Kolárová M
Department of Biochemistry, Faculty of Natural Sciences, Commenius University, Bratislava, Slovakia.
Gen Physiol Biophys. 2008 Jun;27(2):71-84.
Oxidative stress plays an important role in the modulation of several important physiological functions. On the other side, oxidative stress is accountable for development of many unphysiological changes, which can be deleterious for cells. Consequently, at the present time there is increased interest about study mechanisms and changes evocated by oxidative stress. Despite the highly oxidizing environment (21% oxygen, at sea level), at normal conditions, the cell cytoplasm of all aerobic organisms is reduced and proteins contain free sulfhydryl groups. In the cytoplasm, two major systems were identificated responsible for maintaining a reduced state: thioredoxin and glutathione/glutaredoxin system. Thioredoxin in bacteria, thanks to the low redox potential is the major dithiol reductant in the cytosol, or an advanced equivalent to dithiothreitol of cells (Holmgren 1985). Thioredoxin system acts the dominant role in many physiological processes (see below) and it is also a cell antioxidant.
氧化应激在多种重要生理功能的调节中发挥着重要作用。另一方面，氧化应激是许多非生理性变化产生的原因，这些变化可能对细胞有害。因此，目前人们对研究氧化应激引发的机制和变化越来越感兴趣。尽管在海平面时环境具有高氧化性（氧气含量为21%），但在正常情况下，所有需氧生物的细胞质都是还原态的，且蛋白质含有游离巯基。在细胞质中，已确定有两个主要系统负责维持还原状态：硫氧还蛋白和谷胱甘肽/谷氧还蛋白系统。在细菌中，由于硫氧还蛋白的氧化还原电位较低，它是胞质溶胶中的主要二硫醇还原剂，相当于细胞中的二硫苏糖醇的高级等效物（霍尔姆格伦，1985年）。硫氧还蛋白系统在许多生理过程中起主导作用（见下文），它也是一种细胞抗氧化剂。
