Commissariat à l'Energie Atomique (CEA Saclay), iBiTec-S, CNRS URA 2096, Service de Bioénergétique Biologie Structurale et Mécanisme, Bât. 532, 91191 Gif-sur-Yvette, France.
Planta. 2011 Jul;234(1):35-45. doi: 10.1007/s00425-011-1379-y. Epub 2011 Feb 27.
Production of reactive oxygen species (hydroxyl radicals, superoxide radicals and hydrogen peroxide) was studied using EPR spin-trapping techniques and specific dyes in isolated plasma membranes from the growing and the non-growing zones of hypocotyls and roots of etiolated soybean seedlings as well as coleoptiles and roots of etiolated maize seedlings. NAD(P)H mediated the production of superoxide in all plasma membrane samples. Hydroxyl radicals were only produced by the membranes of the hypocotyl growing zone when a Fenton catalyst (FeEDTA) was present. By contrast, in membranes from other parts of the seedlings a low rate of spontaneous hydroxyl radical formation was observed due to the presence of small amounts of tightly bound peroxidase. It is concluded that apoplastic hydroxyl radical generation depends fully, or for the most part, on peroxidase localized in the cell wall. In soybean plasma membranes from the growing zone of the hypocotyl pharmacological tests showed that the superoxide production could potentially be attributed to the action of at least two enzymes, an NADPH oxidase and, in the presence of menadione, a quinone reductase.
采用 EPR 自旋捕获技术和特定染料研究了活性氧（羟基自由基、超氧自由基和过氧化氢）的产生，研究对象为黄化大豆幼苗下胚轴和根的生长区和非生长区、以及黄化玉米幼苗的胚芽鞘和根的分离质膜。NAD(P)H 在所有质膜样品中均介导超氧自由基的产生。只有当存在 Fenton 催化剂（FeEDTA）时，下胚轴生长区的质膜才会产生羟基自由基。相比之下，在幼苗其他部位的质膜中，由于存在少量紧密结合的过氧化物酶，会观察到低速率的自发羟基自由基形成。因此可以得出结论，质外体羟基自由基的产生完全或在很大程度上取决于定位于细胞壁中的过氧化物酶。在黄化大豆幼苗下胚轴生长区的质膜中，药理学测试表明，超氧自由基的产生可能归因于至少两种酶的作用，一种是 NADPH 氧化酶，另一种是在甲萘醌存在下的醌还原酶。
