Metabolomics of Selenium: Se Metabolites Based on Speciation Studies
Metabolomics of Selenium: Se Metabolites Based on Speciation Studies
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DOI：
10.1248/jhs.51.107
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发表时间：
2005-04
影响因子：
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通讯作者：
Kazuo T. Suzuki
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文献类型：
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作者：
Kazuo T. Suzuki
硒是人体正常运转所必需的微量元素。与铜和锌等典型的必需金属相比，这种类金属在新陈代谢方面是非常独特的。本文以物种形成研究为基础，从代谢组学的角度对硒在体内的代谢进行综述。无机和有机形式的硒都可以作为营养来源，它们转化为常见的中间体，硒化物或其等价物。亚硒酸盐和硒酸盐被简单地还原为硒化物以供进一步利用和/或排泄。另一方面，有机硒半胱氨酸直接裂解为硒化物，而硒代蛋氨酸转化为硒半胱氨酸（反硒化途径），类似于蛋氨酸转化为半胱氨酸的反硫化途径，再裂解为硒化物。已知硒化物在tRNA上转化为硒半胱氨酸，硒半胱氨酸残基通过硒半胱氨酸特异性密码子UGA结合到硒蛋白序列中。食物中的各种硒化学物质似乎被认为是硒的种类，并转化为硒化物，然后用于合成硒蛋白。多余的硒从常见的中间硒化物逐步甲基化为甲基化硒代谢物。主要的尿代谢物是1β-甲基硒- n -乙酰- d -半乳糖（硒糖）。三甲基硒已被认为是过量剂量时排泄的尿液代谢物，也是过量剂量的生物学标记物。然而，最近的研究结果与此相矛盾。
Selenium is a trace element essential for the normal function of the body. This metalloid is quite unique in its metabolism compared with typical essential metals such as copper and zinc. In the present communication, the metabolism of selenium in the body was reviewed from the viewpoint of metabolomics based on speciation studies. Both inorganic and organic forms of slenium can be the nutritional source, and they are transformed to the common intermediate, selenide or its equivalent. Selenite and selenate are reduced simply to selenide for further utilization and/or excretion. On the other hand, organic selenocysteine is directly lysed to selenide, while selenomethionine is transformed to selenocysteine (trans-selenation pathway), similarly to the trans-sulfuration pathway for methionine to cysteine, and then lysed to selenide. Selenide is known to be transformed to selenocysteine on tRNA, and the selenocysteinyl residue is incorporated into selenoprotein sequences by the codon specific to selenocysteine, UGA. Diverse selenium chemicals in foods seem to be recognized as selenium species and transformed to selenide, and then utilized for the synthesis of selenoproteins. Surplus selenium is methylated stepwise to methylated selenium metabolites from the common intermediate selenide. The major urinary metabolite is 1β-methylseleno-N-acetyl-D-galactosamine (selenosugar). Trimethylselenonium has been recognized as the urinary metabolite excreted in response to excessive doses and as a biological marker for excessive doses. However, recent results contradicted this.