Ivanov Boris, Borisova-Mubarakshina Maria, Vilyanen Daria, Vetoshkina Daria, Kozuleva Marina
Institute of Basic Biological Problems, Russian Academy of Sciences, Federal Research Center, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Pushchino, Russia.
Biophys Rev. 2022 Jul 20;14(4):857-869. doi: 10.1007/s12551-022-00980-4. eCollection 2022 Aug.
Oxygen reduction in chloroplasts in the light was discovered by (Mehler Arch Biochem Biophys 33:65-77, 1951) as production of hydrogen peroxide. Later, it was shown that the primary product of the oxygen reduction is superoxide radical produced in thylakoids by one-electron transfer from reduced components of photosynthetic electron transport chain to O molecule. For a long time, the formation of hydrogen peroxide was considered to be a result of disproportionation of superoxide radicals in chloroplast stroma. Here, we overview a growing number of evidence indicating on another one, additional to disproportionation, pathway of hydrogen peroxide formation in chloroplasts, namely its formation in thylakoid membrane due to reaction of superoxide radical generated in the membrane with the reduced plastoquinone molecule, plastohydroquinone. Since various components of photosynthetic electron transport chain (primarily photosystem I) can supply superoxide radicals to this reaction, we refer this two-step O photoreduction to HO as a cooperative process. The significance of hydrogen peroxide production via this pathway for redox signaling and scavenging of reactive oxygen species is discussed.
叶绿体在光照下的氧还原是由（Mehler，《生物化学与生物物理学文献》33:65 - 77，1951年）发现的，当时被认为是过氧化氢的产生。后来发现，氧还原的主要产物是类囊体中通过光合电子传递链的还原成分向氧分子单电子转移产生的超氧自由基。长期以来，过氧化氢的形成被认为是叶绿体基质中超氧自由基歧化的结果。在此，我们概述了越来越多的证据，表明除歧化作用外，叶绿体中还有另一条过氧化氢形成途径，即在类囊体膜中，膜内产生的超氧自由基与还原型质体醌分子（质体氢醌）反应导致过氧化氢的形成。由于光合电子传递链的各种成分（主要是光系统I）可以为该反应提供超氧自由基，我们将这种两步氧光还原为过氧化氢的过程称为协同过程。本文讨论了通过该途径产生过氧化氢对氧化还原信号传导和活性氧清除的意义。
