Phung C D, Ezieme J A, Turrens J F
Department of Biomedical Sciences, College of Allied Health Professions, University of South Alabama, Mobile 36688-0002.
Arch Biochem Biophys. 1994 Dec;315(2):479-82. doi: 10.1006/abbi.1994.1528.
The presence of catalase in heart mitochondria may prevent excessive H2O2 from reaching the cytosol, eventually reacting with myoglobin (R. Radi et al., 1991, J. Biol. Chem. 266, 22028-22034). In this report we investigated whether catalase was also present in the mitochondrial matrix of skeletal muscle as it also contains myoglobin which could react with H2O2 produced by mitochondria. Catalase content of skeletal muscle tissue was about 1.4% of that in liver. Simultaneous determinations of citrate synthase (a mitochondrial marker) and catalase in intact mitochondria and mitoplasts indicated that catalase is not associated with muscle mitochondria. The lack of catalase in muscle mitochondria is not due to a limited H2O2 production by these organelles. Rat skeletal muscle mitochondria generated H2O2 (0.64 +/- 0.04 nmol/(min.mg protein), approximately 40% the rate in heart mitochondria. Other groups have shown that training causes an increase in the concentration of mitochondrial electron carriers as well as an increase in the activity of mitochondrial glutathione peroxidase and mitochondrial electron carriers. The increased concentration of mitochondrial electron carriers and the sudden changes in oxygen supply may lead to increased intracellular H2O2 during exercise.
心脏线粒体中过氧化氢酶的存在可能会阻止过量的过氧化氢进入细胞质溶胶，最终与肌红蛋白发生反应（R. Radi等人，1991年，《生物化学杂志》266卷，22028 - 22034页）。在本报告中，我们研究了骨骼肌线粒体基质中是否也存在过氧化氢酶，因为骨骼肌中也含有肌红蛋白，它可能会与线粒体产生的过氧化氢发生反应。骨骼肌组织中的过氧化氢酶含量约为肝脏中的1.4%。对完整线粒体和线粒体膜间隙中柠檬酸合酶（一种线粒体标志物）和过氧化氢酶的同时测定表明，过氧化氢酶与肌肉线粒体无关。肌肉线粒体中缺乏过氧化氢酶并非由于这些细胞器产生过氧化氢的能力有限。大鼠骨骼肌线粒体产生过氧化氢（0.64 ± 0.04 nmol/(min·mg蛋白质)），约为心脏线粒体产生速率的40%。其他研究小组表明，训练会导致线粒体电子载体浓度增加，以及线粒体谷胱甘肽过氧化物酶和线粒体电子载体的活性增加。线粒体电子载体浓度的增加以及氧气供应的突然变化可能会导致运动期间细胞内过氧化氢增加。
