天津体育学院学报

把线粒体看作是细胞制造 ATP的分子热机 ,考虑到呼吸链传递电子时有漏电现象 ,链内传递电子制造 ATP的过程看作是“有用功”,漏出链外的电子未用于制造 ATP是“无用功”,线粒体合成 ATP的效率就是“有用功”和“总功”的比值。计算结果显示效率 E等于 P/ O比值乘以一个系数 f,这个系数 f对以琥珀为底物时是 1 / 2 ,以 NADH为底物时是 1 / 3(郑红英 ,徐建兴 .生物物理学报 ,1 999,1 5 :6 47～6 5 4)。用两类底物测试线粒体的 P/ O比值所得数字有所不同 ,但按此原理计算出线粒体合成 ATP的效率应当是同一数值 ,这一点在鼠肝线粒体测得的数据中得到了较好的吻合。体育运动时机体消耗大量的 ATP,因此线粒体合成 ATP的效率对运动员的体力和耐力具有相关性意义。将此原理用于运动疲劳的分析 ,可以得到一些有益的启示

On account of the phenomenon of electron leak of mitochondrial respiratory chain,the mitochondria could be treated as a molecular heat engine on ATP synthesis.The leaked electrons not used in the ATP synthesis could be treated as“unavailable work”while the transferred electrons coupled with ATP synthesis could be treated as“available work”.Then the efficiency of ATP synthesis in mitochondria could be defined as the ratio of“available work”to the“total work”(“available work”+“unavailable work”).The result showed the efficiency E=f×(P/O),here coefficient f equal to 1/2 for the substrate of succinate and 1/3 for the substrate of NADH (Zheng Hong ying and Xu Jian xing,Acta Biophysica Sinica,1999,15:647～654).The P/O ratio was different under two kinds of substrate but the efficiency calculated according to such equation should be the same.This conclusion was proved in a determination of rat liver mitochondria.Physical competition made sportsman spend a lot of ATP,therefore the efficiency of ATP synthesis in mitochondria was closely related to exercise induced fatigue.A group of data was given to show that the efficiency of mitochondrial ATP synthesis was lower during exercise induced fatigue in rat.The factors affecting the efficiency were discussed with this theory.