کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1909417 | 1046723 | 2010 | 6 صفحه PDF | دانلود رایگان |
Superoxide reductase (SOR) is an enzyme that converts superoxide into hydrogen peroxide at a twofold higher yield than canonical superoxide dismutases (SOD). Superoxide radical detection was investigated using the Amplex red (AR)/peroxidase system to measure the difference in hydrogen peroxide production yield in the presence of SOR or SOD. We found that reduced SOR reacts with the AR oxidation intermediate, a one-electron reduced AR
• radical, by reducing this intermediate back to the initial AR leuco compound. Ascorbate also quenched this radical in a concentration-dependent manner and could be used to compete efficiently with SOR; at concentrations of ascorbate higher than 5 µM, SOR no longer interfered with the detection of H2O2. By using xanthine/xanthine oxidase as a superoxide-generating system, it was possible to successfully quantify superoxide and hydrogen peroxide in vitro using the AR/peroxidase/SOR system, either by visible absorption or by fluorescence emission, with a considerable low detection limit of 10 nM/min. The use of enzymes with diffusion-limited reactivity toward superoxide substantially increases specificity and detection threshold for superoxide and turns this approach into a powerful system to detect ROS in biological systems.
Journal: Free Radical Biology and Medicine - Volume 49, Issue 1, 1 July 2010, Pages 61–66