类囊体膜光系统Ⅱ中超氧阴离子生成机制的研究

Studies on Superoxide Formation in Photosystem Ⅱ with a Novel Spin Trap

对高等植物类囊体膜的研究表明，易于损伤生物体的超氧阴离子自由基（O2- ）可以在其光系统Ⅱ（PSⅡ）中大量生成，并且可能是导致光系统的光抑制和光破坏现象的主要根源之一[1－3]．然而，由于超氧阴离子自由基化学性质活泼，而且生物体中含量很低，因此受物理检测手段的局限，对于PSⅡ中O2-的生成机制所知甚少．

Abstract Under strong illumination, photosystem Ⅱ (PS Ⅱ )of higher plant was active in superoxide production. However, it keeps unclear about the mechanisms and sites of superoxide formation by PS Ⅱ . Concerning above questions, the molecular mechanisms of superoxide formation by PS II from spinach in this work has been studied. The site range for possible superoxide formation by PS I has been constricted by the study on the donor or acceptor inhibited PS I preparation. The results indicated that the plasto-quinones located at QA and QB of PS I was the primary site responsible for superoxide formation.