Tungstate: is it really a specific nitrate reductase inhibitor in plant nitric oxide research?
Tungstate: is it really a specific nitrate reductase inhibitor in plant nitric oxide research?
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DOI：
10.1093/jxb/err268
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发表时间：
2012
影响因子：
6.9
通讯作者：
J. Xiong;G. Fu;Yongjie Yang;Cheng Zhu;L. Tao
中科院分区：
文献类型：
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作者：
J. Xiong;G. Fu;Yongjie Yang;Cheng Zhu;L. Tao
硝酸还原酶（NR）是植物中一氧化氮（NO）的酶源，它需要钼来激活钼辅因子。由于NR缺陷突变体在某些物种中并不总是可用的，因此钨酸盐作为竞争性拮抗剂替代Mo-辅因子中的Mo的廉价且简单的药理学应用被广泛用作植物NO研究中的NR抑制剂。然而，有证据表明，钨酸盐不仅使NR失活，而且还抑制植物中其他依赖于钨酸盐的酶。此外，大量研究表明，钨酸盐也抑制根的生长，影响皮层微管的形成，并诱导植物细胞程序性死亡（PCD），就像其他重金属一样。因此，钨酸盐已被证明发挥许多与NR活性抑制无关的其他作用。本文综述了钨酸盐作为植物NR抑制剂的来源和作用机理，分析了钨酸盐对植物的毒性研究进展以及在植物NO研究中应用钨酸盐作为NR抑制剂可能存在的问题。总之，在植物NO研究中使用钨酸盐作为NR抑制剂必须谨慎对待，记住它不是完全特异性的。寻找更多的NR缺陷突变体和新的特异性NR抑制剂是必要的。为了研究NO在植物中的作用，将药理学和生物化学分析与遗传学方法相结合是必要的。
Nitrate reductase (NR) is an enzymatic source of nitric oxide (NO) in plants, and it needs Mo for the Mo-cofactor to be activated. Because NR-deficient mutants are not always available in some species, a cheap and simple pharmacological application of tungstate, which substitutes for Mo in the Mo-cofactor as a competitive antagonist, is widely used as a NR inhibitor in plant NO research. However, evidence indicates that tungstate not only inactivates NR but also inhibits other molybdate-dependent enzymes in plants. In addition, a number of investigations have shown that tungstate also inhibits root growth, affects cortical microtubule formation, and induces programmed cell death (PCD) in plants, just like other heavy metals do. Therefore, tungstate has been shown to exert many other effects that are not connected with the inhibition of NR activity. The origin and mechanism of using tungstate as a NR inhibitor in plants is reviewed here and the progress regarding tungstate toxicity to plants and the possible problems involved in using tungstate as a NR inhibitor in plant NO research are analysed. In summary, the use of tungstate as a NR inhibitor in plant NO research must be treated with caution, keeping in mind that it is not completely specific. It is necessary to search for more NR-deficient mutants and new, specific NR inhibitors. A combination of pharmacological and biochemical analysis with a genetic approach will be necessary in order to investigate the roles of NO in plants.