Sgherri C L, Pinzino C, Samaritani E, Navari-Izzo F
Dipartimento di Chimica e Biotecnologie Agrarie, Università degli Studi di Pisa, Italy.
Free Radic Res. 1999 Dec;31 Suppl:S199-204. doi: 10.1080/10715769900301511.
Using a novel phosphorylated spin trap, 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide (DEPMPO), an analogue of the commonly used spin trap 5,5'-dimethyl-1-pyrroline N-oxide (DMPO), we have investigated the production of oxygen radical species under illumination of thylakoids from wheat (Triticum durum Desf cv. Ofanto). DEPMPO reacted with superoxide (O2*-) and hydroxyl radical (HO*) forming distinctive spin trap adducts. Spectra of (O2*-) and HO* adducts of DEPMPO were recorded in the presence of xanthine/xanthine oxidase and FeSO4/H2O2, respectively, and computer simulation of spectra was performed. During illumination of thylakoids both O2*- and HO* were detected as well. Transition metals catalysed transformation of O2*- into HO*. The conversion was enhanced by H2O2 and prevented by exogenous superoxide dismutase and catalase. The presence of a thylakoid-bound superoxide dismutase, whose activity was inhibited by H2O2 and diethyldithiocarbamic acid, was responsible for H2O2 production from O2*- and thus for HO* generation.
我们使用一种新型的磷酸化自旋捕捉剂5-(二乙氧基磷酰基)-5-甲基-1-吡咯啉-N-氧化物（DEPMPO），它是常用自旋捕捉剂5,5'-二甲基-1-吡咯啉-N-氧化物（DMPO）的类似物，研究了小麦（硬粒小麦品种奥凡托）类囊体光照下氧自由基的产生。DEPMPO与超氧阴离子（O2*-）和羟基自由基（HO*）反应形成独特的自旋捕捉加合物。分别在黄嘌呤/黄嘌呤氧化酶和硫酸亚铁/过氧化氢存在的情况下记录DEPMPO的（O2*-）和HO加合物的光谱，并进行光谱的计算机模拟。在类囊体光照过程中也检测到了O2-和HO*。过渡金属催化O2*-转化为HO*。过氧化氢增强了这种转化，而外源性超氧化物歧化酶和过氧化氢酶则阻止了这种转化。类囊体结合的超氧化物歧化酶的存在导致了由O2*-产生过氧化氢，进而导致HO*的产生，其活性受到过氧化氢和二乙基二硫代氨基甲酸的抑制。
