Copper-release from yeast Cu(I)-metallothionein by nitric oxide (NO)
Copper-release from yeast Cu(I)-metallothionein by nitric oxide (NO)
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DOI：
10.1023/a:1009275122084
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发表时间：
2000-06-01
期刊：
影响因子：
3.5
通讯作者：
Weser, U
中科院分区：
文献类型：
--
作者：
Hartmann, HJ;Weser, U
研究了酵母 Cu-MT 与一氧化氮 (NO) 的反应。在体外观察到这种非常重要的试剂从蛋白质的 Cu(I)-硫醇盐簇中释放出铜。通过紫外电子吸收、圆二色性和发光发射监测，在每当量硫因铜表达两倍摩尔过量的 NO 的情况下，Cu(I)-硫醇盐发色团的特征光谱信号趋于平稳。同时所有的铜都可以被 EPR 检测到。通过凝胶过滤可以很容易地从蛋白质部分去除氧化的金属离子。铜释放过程的可逆性特别令人感兴趣。先前脱金属的蛋白质的特异性荧光和二向色特性在还原条件下可以恢复高达 85%。此外，与未处理的 Cu-MT 相比，未发现电泳行为有任何差异。因此，NO 可能作为 Cu-MT 瞬时铜释放的有效代谢源。在氧化爆发过程中，这种高芬顿活性的铜能够提高生物防御机制的功效。
The reaction of yeast Cu-MT with nitric oxide (NO) was examined. A release of copper from the Cu(I)-thiolate clusters of the protein by this remarkably important reagent was observed in vitro. The characteristic spectroscopic signals of the Cu(I)-thiolate chromophores levelled off in the presence of a two-fold molar excess of NO expressed per equivalent of thionein-copper as monitored by UV-electronic absorption, circular dichroism and luminescence emission. At the same time all of the copper became EPR detectable. The oxidized metal ions could easily be removed from the protein moiety by gelfiltration. The reversibility of the copper releasing process is of special interest. The specific fluorescence and dichroic properties of the previously demetallized protein could be recovered up to 85% under reductive conditions. Moreover, no difference in the electrophoretic behaviour was seen compared to the untreated Cu-MT. Thus, NO may act as a potent metabolic source for the transient copper release from Cu-MT. In the course of an oxidative burst this highly Fenton active copper is able to improve the efficacy of biological defence mechanisms.