Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Russia.
Physiol Plant. 2010 Oct;140(2):103-10. doi: 10.1111/j.1399-3054.2010.01391.x.
Reactive oxygen species (ROS) resulting from oxygen reduction, superoxide anion radical O2(*-) and hydrogen peroxide H(2)O(2) are very significant in the cell metabolism of aerobic organisms. They can be destructive and lead to apoptosis and they can also serve as signal molecules. In the light, chloroplasts are known to be one of the main sources of ROS in plants. However, the components involved in oxygen reduction and the detailed chemical mechanism are not yet well established. The present review describes the experimental data and theoretical considerations that implicate the plastoquinone pool (PQ-pool) in this process. The evidence indicates that the PQ-pool has a dual role: (1) the reduction of O(2) by plastosemiquinone to superoxide and (2) the reduction of superoxide by plastohydroquinone to hydrogen peroxide. The second role represents not only the scavenging of superoxide, but also the generation of hydrogen peroxide as an important signaling molecule. The regulatory and protective functions of the PQ-pool are discussed in the context of these reactions.
活性氧（ROS）是氧还原产生的，超氧阴离子自由基 O2(*-)和过氧化氢 H(2)O(2)在需氧生物的细胞代谢中非常重要。它们具有破坏性，可导致细胞凋亡，也可以作为信号分子。众所周知，在光照条件下，叶绿体是植物中 ROS 的主要来源之一。然而，参与氧还原的成分和详细的化学机制尚未得到很好的确定。本综述描述了表明质体醌库（PQ-库）在该过程中起作用的实验数据和理论考虑。有证据表明，PQ-库具有双重作用：（1）质体半醌将 O(2)还原为超氧自由基，（2）质体氢醌将超氧自由基还原为过氧化氢。第二个作用不仅代表了超氧自由基的清除，还代表了过氧化氢的产生，作为一种重要的信号分子。讨论了 PQ-库在这些反应中的调节和保护功能。
