Davies N T, Lawrence C B
Biochim Biophys Acta. 1986 Mar 12;848(3):294-304. doi: 10.1016/0005-2728(86)90203-3.
Liver mitochondria from Cu-deficient rats exhibit impaired State 3 respiration (oxygen consumption in the presence of exogenous ADP) compared with Cu-adequate controls, whereas State 4 respiration (oxygen consumption after depletion of exogenous ADP) and ADP/O are unaffected. In view of previous observations (Davies, N.T., Lawrence, C.B., Mills, C.F. and Nicol, F. (1985) Biochim. Biophys. Acta 809, 351-361) it seemed that a decline in cytochrome c oxidase activity (EC 1.9.3.1) could not fully account for these findings. Cu deficiency resulted in a significant decline (40%, P less than 0.01) in [14C]ADP uptake by liver mitochondria which suggests there is a reduced activity of the adenine nucleotide translocase. The reduced translocase activity was not associated with any marked change in fatty-acid composition of either intact mitochondria or inner mitochondrial membranes. Inhibitor titrations with the irreversible inhibitor carboxyatractyloside showed that 'Cu-deficient' mitochondria required the same concentration of inhibitor to produce 100% inhibition of State 3 respiration as control mitochondria, suggesting that the amount of functional translocase enzyme present is unaffected. When the translocase assay was allowed to proceed until equilibrium was established between external and internal nucleotides, it was apparent that the exchangeable adenine nucleotide pool of Cu-deficient mitochondria was 36% lower than in controls. Analysis of mitochondria for their ATP, ADP and AMP contents showed that, whereas the AMP content was unaffected, ATP and ADP contents were 39 and 40% lower, respectively, which resulted in a significantly reduced pool of total adenine nucleotides (ATP + ADP + AMP) and a reduced 'energy charge' [(ATP + 0.5 ADP)/(ATP + ADP + AMP)]. These results are discussed in relation to current concepts of the regulation and control of mitochondrial respiration.
与铜充足的对照组相比，缺铜大鼠的肝脏线粒体在状态3呼吸（存在外源性ADP时的氧气消耗）方面表现出受损，而状态4呼吸（外源性ADP耗尽后的氧气消耗）和ADP/O不受影响。鉴于之前的观察结果（戴维斯，N.T.，劳伦斯，C.B.，米尔斯，C.F.和尼科尔，F.（1985年）《生物化学与生物物理学报》809，351 - 361），细胞色素c氧化酶活性（EC 1.9.3.1）的下降似乎不能完全解释这些发现。铜缺乏导致肝脏线粒体对[14C]ADP的摄取显著下降（40%，P小于0.01），这表明腺嘌呤核苷酸转位酶的活性降低。转位酶活性降低与完整线粒体或线粒体内膜的脂肪酸组成的任何显著变化均无关。用不可逆抑制剂羧基苍术苷进行的抑制剂滴定表明，“缺铜”线粒体与对照线粒体产生100%状态3呼吸抑制所需的抑制剂浓度相同，这表明存在的功能性转位酶的量未受影响。当转位酶测定进行到外部和内部核苷酸之间建立平衡时，很明显缺铜线粒体的可交换腺嘌呤核苷酸池比对照低36%。对线粒体的ATP、ADP和AMP含量进行分析表明，虽然AMP含量未受影响，但ATP和ADP含量分别降低了39%和40%，这导致总腺嘌呤核苷酸池（ATP + ADP + AMP）显著减少，“能量电荷”[(ATP + 0.5 ADP)/(ATP + ADP + AMP)]降低。结合线粒体呼吸调节和控制的当前概念对这些结果进行了讨论。
