Division of Bioindustrial Science, Graduate School of Life and Environmental Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
J Biosci Bioeng. 2010 Jun;109(6):638-44. doi: 10.1016/j.jbiosc.2009.11.016. Epub 2010 Jan 19.
A new and simple method based on the mechanism of detoxification of metallothionein was developed by using a water-soluble porphyrin and Zn(II)-bound metallothionein for evaluating heavy metal toxicity. Labile Zn(II) ions were released when toxic metal ions such as Cu(II), Pb(II), Bi(III), Cd(II), Hg(II), Co(II), Ag(I), and Ni(II) bound to Zn(II)-bound metallothionein. The water-soluble porphyrin, 5,10,15,20-tetraphenyl-21H,23H-porphinetetrasulfonic acid, a chromogenic reagent that is highly sensitive to Zn(II), formed a complex with the labile Zn(II) ions. The absorption change at 423 nm resulting from the formation of the Zn(II)-porphyrin complex was used to evaluate the toxicity of sample solutions containing different metal ions. The absorption change was well correlated with the toxicity, which was evaluated by a bioluminescence inhibition assay using the bioluminescent bacteria Vibrio fischeri. This observation indicated that the absorption change determined by our method was a good indicator of heavy metal toxicity. The proposed method was more sensitive than conventional bioassays and could be used to detect metal toxicity at submicromolar concentrations of toxic metal ions.
一种基于金属硫蛋白解毒机制的新的简单方法已经被开发出来，该方法使用水溶性卟啉和 Zn(II)结合的金属硫蛋白来评估重金属毒性。当有毒金属离子如 Cu(II)、Pb(II)、Bi(III)、Cd(II)、Hg(II)、Co(II)、Ag(I)和 Ni(II)与 Zn(II)结合的金属硫蛋白结合时，会释放出可利用的 Zn(II)离子。水溶性卟啉，5,10,15,20-四苯基-21H,23H-卟啉四磺酸，是一种对 Zn(II)高度敏感的显色试剂，与可利用的 Zn(II)离子形成配合物。形成 Zn(II)-卟啉配合物引起的 423nm 处的吸光度变化可用于评估含有不同金属离子的样品溶液的毒性。吸光度变化与毒性密切相关，这是通过使用发光细菌 Vibrio fischeri 的生物发光抑制试验来评估的。这一观察结果表明，我们的方法所确定的吸光度变化是重金属毒性的一个很好的指标。该方法比传统的生物测定法更灵敏，可用于检测亚微摩尔浓度的有毒金属离子的金属毒性。
