MITOCHONDRIAL GENERATION OF HYDROGEN-PEROXIDE - GENERAL PROPERTIES AND EFFECT OF HYPERBARIC-OXYGEN
MITOCHONDRIAL GENERATION OF HYDROGEN-PEROXIDE - GENERAL PROPERTIES AND EFFECT OF HYPERBARIC-OXYGEN
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DOI：
10.1042/bj1340707
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发表时间：
1973-01-01
影响因子：
4.1
通讯作者：
CHANCE, B
中科院分区：
文献类型：
--
作者：
BOVERIS, A;CHANCE, B
1.鸽子心脏线粒体产生H2 O2的最大速率约为20 nmol/min/mg蛋白质。2.琥珀酸-谷氨酸和苹果酸-谷氨酸是能够支持最大H2 O2产生速率的底物。在苹果酸-谷氨酸盐中，H2 O2的形成对鱼藤酮敏感。内源性底物辛酸盐、硬脂酰辅酶A和棕榈酰肉毒碱是效率低得多的底物。3.抗霉素A对鸽子心肌线粒体产生H_2O_2有显著的促进作用，每毫克蛋白质中加入0.26nmol抗霉素A和一种解偶联剂可使H_2O_2产生最大量。4.在内源性底物和抗霉素A存在下，ATP减少，解偶联剂恢复H2 O2形成速率。5.泛醌-10和泛醌-3到泛醌耗尽的鸽子心脏线粒体的再掺入给出了一个系统，其中H2 O2的产生与掺入的泛醌线性相关。6.在琥珀酸-谷氨酸存在下和代谢状态4下，鸽子心脏线粒体产生H2 O2的最佳pH值为7.5。在状态1和3u中，在抗霉素A和解偶联剂的存在下，最佳pH值向更碱性的值移动。7.随着高压区O2分压的增加，鸽子心脏线粒体和大鼠肝脏线粒体中H2 O2的形成显着增加。以大鼠肝线粒体和琥珀酸为底物，在状态4下，pO_2增加到1.97MPa（19.5atm），H_2O_2的生成增加10-15倍。当大鼠肝线粒体补充抗霉素A或抗霉素A和解偶联剂时，观察到类似的pO 2曲线。在1.97MPa（19.5atm）压力下没有观察到O2饱和。在代谢状态4下，以琥珀酸为底物，当pO_2增加到1.97MPa（19.5atm）时，鸽心肌线粒体中H_2O_2的生成量增加了4倍，加入抗霉素A时增加了3倍，加入抗霉素A和解偶联剂时增加了2.5倍。在后两种情况下，观察到系统被氧饱和，表观Km约为71 kPa（0.7-0.8atm），aVmax为12和20 nmol H_2O_2/min/mg蛋白质。8.据推测，除了众所周知的黄素反应，H2 O2的形成可能是由于在细胞色素水平上与呼吸链的能量依赖性组分相互作用。
1. Pigeon heart mitochondria produce H2O2at a maximal rate of about 20nmol/min per mg of protein. 2. Succinate–glutamate and malate–glutamate are substrates which are able to support maximal H2O2production rates. With malate–glutamate, H2O2formation is sensitive to rotenone. Endogenous substrate, octanoate, stearoyl-CoA and palmitoyl-carnitine are by far less efficient substrates. 3. Antimycin A exerts a very pronounced effect in enhancing H2O2production in pigeon heart mitochondria; 0.26nmol of antimycin A/mg of protein and the addition of an uncoupler are required for maximal H2O2formation. 4. In the presence of endogenous substrate and of antimycin A, ATP decreases and uncoupler restores the rates of H2O2formation. 5. Reincorporation of ubiquinone-10 and ubiquinone-3 to ubiquinone-depleted pigeon heart mitochondria gives a system in which H2O2production is linearly related to the incorporated ubiquinone. 6. The generation of H2O2by pigeon heart mitochondria in the presence of succinate–glutamate and in metabolic state 4 has an optimum pH value of 7.5. In states 1 and 3u, and in the presence of antimycin A and uncoupler, the optimum pH value is shifted towards more alkaline values. 7. With increase of the partial pressure of O2to the hyperbaric region the formation of H2O2is markedly increased in pigeon heart mitochondria and in rat liver mitochondria. With rat liver mitochondria and succinate as substrate in state 4, an increase in the pO2up to 1.97MPa (19.5atm) increases H2O2formation 10–15-fold. Similar pO2profiles were observed when rat liver mitochondria were supplemented either with antimycin A or with antimycin A and uncoupler. No saturation of the system with O2was observed up to 1.97MPa (19.5atm). By increasing the pO2to 1.97MPa (19.5atm), H2O2formation in pigeon heart mitochondria with succinate as substrate increased fourfold in metabolic state 4, with antimycin A added the increase was threefold and with antimycin A and uncoupler it was 2.5-fold. In the last two saturation of the system with oxygen was observed, with an apparentKmof about 71kPa (0.7–0.8atm) and aVmax.of 12 and 20nmol of H2O2/min per mg of protein. 8. It is postulated that in addition to the well-known flavin reaction, formation of H2O2may be due to interaction with an energy-dependent component of the respiratory chain at the cytochromeblevel.