Decrease in heart mitochondrial creatine kinase activity due to oxygen free radicals
1Third Department of Internal Medicine, Hamamatsu University School of Medicine, Japan.
Abstract:
This study was undertaken to examine the effects of oxygen free radicals on mitochondrial creatine kinase activity in rat heart. Xanthine plus xanthine oxidase (superoxide anion radical generating system) reduced mitochondrial creatine kinase activity both in a dose- and a time-dependent manner. Superoxide dismutase showed a protective effect on depression in creatine kinase activity due to xanthine plus xanthine oxidase. Hydrogen peroxide inhibited creatine kinase activity in a dose-dependent manner, this inhibition was protected by the addition of catalase. In order to understand the detailed mechanisms by which oxygen free radicals inhibit mitochondrial creatine kinase activity, the effects of oxygen free radicals on mitochondrial sulfhydryl groups were examined. Mitochondrial sulfhydryl groups contents were decreased by xanthine plus xanthine oxidase or hydrogen peroxide; this depression in sulfhydryl groups contents was prevented by the addition of superoxide dismutase or catalase. N-Ethylmaleimide (sulfhydryl group reagent) expressed inhibitory effects on the creatine kinase activity both in a dose- and a time-dependent manner; dithiothreitol or cysteine (sulfhydryl group reductant) showed protective effects on the creatine kinase activity depression induced by N-ethylmaleimide. Dithiothreitol or cysteine also blocked the depression of mitochondrial creatine kinase activity caused by xanthine plus xanthine oxidase or hydrogen peroxide. These results lead us to conclude that oxygen free radicals may inhibit mitochondrial creatine kinase activity by modifying sulfhydryl groups in the enzyme protein.
More Related Videos
12:22Ratiometric Biosensors that Measure Mitochondrial Redox State and ATP in Living Yeast Cells
Published on: July 22, 2013
09:40Phosphorus-31 Magnetic Resonance Spectroscopy: A Tool for Measuring In Vivo Mitochondrial Oxidative Phosphorylation Capacity in Human Skeletal Muscle
Published on: January 19, 2017
Related Concept Videos
Mitochondria
Mitochondrial Membranes
Electron Transport Chain: Complex I and II
ROS generation is regulated and maintained at moderate levels necessary...
The Electron Transport Chain
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q in...
Electron Transport Chain: Complex III and IV
Muscle Recovery and Fatigue
