Kuznetsov A V, Clark J F, Winkler K, Kunz W S
Laboratory of Neurobiochemistry, Klinik für Neurologie, Universitätsklinikum, Magdeburg, Germany.
J Biol Chem. 1996 Jan 5;271(1):283-8. doi: 10.1074/jbc.271.1.283.
The brindled mottled mouse (Mobr), an animal model of the Menkes' copper deficiency syndrome, was used for the investigation of changes in respiratory flux control associated with cytochrome c oxidase deficiency in muscle. Enzymatic analysis of cardiac and skeletal muscles showed an approximately 2-fold decrease in cytochrome c oxidase activity of brindled mutants in both types of muscles as compared with controls. The activities of NADH-cytochrome c oxidoreductase (respiratory chain segment I-III) and succinate-cytochrome c oxidoreductase (segment II-III) were normal. Assessment of mitochondrial respiratory function was performed using chemically skinned musculus quadriceps or heart muscle fibers isolated from control and brindled mottled mice. In skeletal muscle, there was no difference found in maximal rates of respiration. In the Mobr hearts, this parameter was slightly lower than control. Alternately, the determination of flux control coefficients of cytochrome c oxidase performed by a step by step inhibition of respiration with increasing concentrations of azide or cyanide revealed significantly sharper inhibition curves for brindled mice than for control, indicating more than 2-fold elevated flux control coefficients of cytochrome c oxidase. This investigation proved essential in characterizing the metabolic effect of a cytochrome c oxidase deficiency. We conclude, therefore, that application of metabolic control analysis can be a valuable approach to study defects of mitochondrial oxidative phosphorylation.
花斑斑驳小鼠（Mobr）是门克斯铜缺乏综合征的动物模型，用于研究与肌肉中细胞色素c氧化酶缺乏相关的呼吸通量控制变化。对心脏和骨骼肌的酶分析表明，与对照组相比，两种类型肌肉中花斑突变体的细胞色素c氧化酶活性均下降了约2倍。NADH - 细胞色素c氧化还原酶（呼吸链片段I - III）和琥珀酸 - 细胞色素c氧化还原酶（片段II - III）的活性正常。使用从对照和花斑斑驳小鼠分离的化学去皮股四头肌或心肌纤维进行线粒体呼吸功能评估。在骨骼肌中，未发现最大呼吸速率有差异。在Mobr心脏中，该参数略低于对照组。另外，通过用叠氮化物或氰化物浓度增加逐步抑制呼吸来测定细胞色素c氧化酶的通量控制系数，结果显示花斑小鼠的抑制曲线比对照组明显更陡，表明细胞色素c氧化酶的通量控制系数提高了2倍以上。这项研究对于表征细胞色素c氧化酶缺乏的代谢效应至关重要。因此，我们得出结论，代谢控制分析的应用可能是研究线粒体氧化磷酸化缺陷的一种有价值的方法。
