Comparison of the effects of superoxide dismutase and cytochrome c on luminol chemiluminescence produced by xanthine oxidase-catalyzed reactions |
| |
| Authors: | R A Radi H Rubbo E Prodanov |
| |
| Institution: | Department of Biochemistry, Faculty of Medicine, Universidad de la República, Montevideo, Uruguay. |
| |
| Abstract: | Superoxide dismutase (superoxide: superoxide oxidoreductase, EC 1.15.1.1) (SOD) and ferricytochrome c are used to check the effects on luminol chemiluminescence induced by a xanthine or hypoxanthine/xanthine oxidase/oxygen system. Luminol chemiluminescence has been attributed to superoxide anion radical (O2.-) in this system. From kinetic studies on the light intensity vs. time curves it is demonstrated that addition of SOD into the system does not affect the mechanism of O2.- generation, whilst ferricytochrome c dramatically alters the time-course of the reaction. This is interpreted as the effect of cytochrome c redox cycling by reaction with H2O2, modifying oxy-radical generation in the reaction medium. Also, an alternative mechanism for luminol chemiexcitation is proposed under certain experimental conditions. |
| |
| Keywords: | |
|
|
