Leblondel G, Allain P
J Inorg Biochem. 1984 Jul;21(3):241-51. doi: 10.1016/0162-0134(84)83007-x.
A comparative study of the Cu2+ effects, binding and reduction, has been performed on rat liver mitochondria. In the first minutes, Cu2+ (less than or equal to 50 micron) is massively bound and reduced to the extent of 70%-80% while a simultaneous activation of respiration takes place. Then the remaining 20% or so of Cu2+ are progressively bound and reduced while respiratory inhibition, Ca2+ and Mg2+ effluxes, and swelling are observed. EDTA, used as a copper chelator, prevents or reduces the copper effects and removes part of the bound copper, according to the time of introduction in the incubation medium after Cu2+. The results suggest that the two steps of the copper binding and the effects following involve mainly first the outer (cytosol side) proteins of the inner membrane and then those of the inner membrane. 100 microM dithiothreitol and 100 microM glutathione used as antioxidant thiol reagents prevent, as does EDTA, but do not reverse the 25 microM copper effects. They also decrease the copper binding; however, no relationship between binding and preventive action is observed. It is shown that glutathione and dithiothreitol have a specific potent ability to reduce Cu2+, which explains that in presence of these reagents copper may react with mitochondria partly or entirely in the form of Cu+. These findings suggest that Cu2+ in its Cu+ form has no mitochondrial effect. A mechanism of copper action involving oxidation of some membrane thiol groups is discussed.
对大鼠肝脏线粒体进行了铜离子（Cu2+）效应、结合及还原的比较研究。在最初几分钟内，Cu2+（小于或等于50微摩尔）大量结合并还原，还原程度达70%-80%，同时呼吸作用被激活。然后，剩余约20%的Cu2+逐渐结合并还原，同时观察到呼吸抑制、钙离子（Ca2+）和镁离子（Mg2+）外流以及肿胀现象。乙二胺四乙酸（EDTA）作为一种铜螯合剂，根据其在Cu2+加入孵育介质后的引入时间，可预防或减轻铜离子效应，并去除部分结合的铜。结果表明，铜离子结合的两个步骤及其后续效应主要首先涉及内膜的外（胞质侧）蛋白，然后是内膜蛋白。100微摩尔二硫苏糖醇和100微摩尔谷胱甘肽作为抗氧化硫醇试剂，与EDTA一样可预防，但不能逆转25微摩尔铜离子的效应。它们还会减少铜离子的结合；然而，未观察到结合与预防作用之间的关系。结果表明，谷胱甘肽和二硫苏糖醇具有特定的强大还原Cu2+的能力，这解释了在这些试剂存在的情况下，铜可能部分或完全以Cu+的形式与线粒体发生反应。这些发现表明，Cu+形式的Cu2+对线粒体没有作用。本文讨论了一种涉及某些膜硫醇基团氧化的铜离子作用机制。
