Webb M, Magos L, Holt D
Chem Biol Interact. 1980 Oct;32(1-2):137-49. doi: 10.1016/0009-2797(80)90073-3.
The metallothionein fractions, isolated by gel filtration from the kidneys of rats that have been dosed with Cd2+, Hg2+ or Cd2+ followed by Hg2+, yield very different elution profiles on ion-exchange chromatography. The metallothionein from Cd2+-treated animals is resolved into the isomethallothioneins I and II and a minor, less negatively-charged species (B), which contains Cd2+ and copper, but little Zn2+. The corresponding fraction from the kidneys of rats doses with Hg2+ yields five components, all of which contain Hg2+, Zn2+ and Cu, but in different ratios. Three of these compounds correspond in their elution characteristics from DE-cellulose with the above-mentioned isometallothioneins I and II and fraction B. The last of these, which also is rich in Cu, is the major Hg2+-binding component. The distribution of Hg2+ and of other cations between these five sub-fractions, but not the number of sub-fractions, is altered by Cd2+-pretreatment of the animals. Treatment of Cd2+-dosed rats with sodium maleate has no significant effect on the distribution of cations (Cd2+, Zn2+ and copper) amongst the renal metallothionein subfractions. The same treatment, applied to animals dosed with either Hg2+ only, or Cd2+ followed by Hg2+, causes the elimination of 70--75% of the Hg2+ from the metallothionein fraction. Loss occurs from all subfractions, but is greatest in subfraction B, which also loses copper. Whilst it is possible that Hg2+ may induce metallothionein and other metalloproteins in the kidney, Hg2+ appears to bind to both isometallothioneins I and II, when these are induced by Cd2+-pretreatment. The loss of Hg2+, but not of Cd2+, from these metalloproteins after treatment with sodium maleate may be related to differences in the relative binding affinities of the two cations for thionein and other cellular proteins.
通过凝胶过滤从经Cd2+、Hg2+或先给予Cd2+再给予Hg2+处理的大鼠肾脏中分离得到的金属硫蛋白组分，在离子交换色谱上呈现出非常不同的洗脱图谱。来自Cd2+处理动物的金属硫蛋白可分离为异金属硫蛋白I和II以及一种带负电荷较少的次要组分（B），该组分含有Cd2+和铜，但锌含量很少。来自Hg2+处理大鼠肾脏的相应组分产生五个组分，所有组分均含有Hg2+、Zn2+和Cu，但比例不同。其中三种化合物从DE - 纤维素上的洗脱特性与上述异金属硫蛋白I和II以及组分B相对应。最后一种富含铜的化合物是主要的Hg2+结合组分。动物经Cd2+预处理后，这五个亚组分之间Hg2+和其他阳离子的分布会发生改变，但亚组分的数量不变。用马来酸钠处理经Cd2+给药的大鼠，对肾脏金属硫蛋白亚组分中阳离子（Cd2+、Zn2+和铜）的分布没有显著影响。同样的处理应用于仅给予Hg2+或先给予Cd2+再给予Hg2+的动物，会导致金属硫蛋白组分中70 - 75%的Hg2+被去除。所有亚组分都会出现损失，但在组分B中损失最大，该组分同时也会损失铜。虽然Hg2+可能会诱导肾脏中的金属硫蛋白和其他金属蛋白，但当这些蛋白由Cd2+预处理诱导产生时，Hg2+似乎会与异金属硫蛋白I和II都结合。用马来酸钠处理后，这些金属蛋白中Hg2+的损失而非Cd2+的损失，可能与这两种阳离子对硫蛋白和其他细胞蛋白的相对结合亲和力差异有关。
