Metabolism of 76Se-methylselenocysteine compared with that of 77Se-selenomethionine and 82Se-selenite.
Metabolism of 76Se-methylselenocysteine compared with that of 77Se-selenomethionine and 82Se-selenite.
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DOI：
10.1016/j.taap.2006.09.006
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发表时间：
2006-12
影响因子：
3.8
通讯作者：
Kazuo T. Suzuki;C. Doi;N. Suzuki
中科院分区：
文献类型：
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作者：
Kazuo T. Suzuki;C. Doi;N. Suzuki
硒甲基化硒氨基酸，硒甲基硒半胱氨酸（MeSeCys）和硒代蛋氨酸（SeMet）是硒积累器中硒的化学惰性储存形式，也是一种营养和补充来源。MeSeCys的代谢途径参照了SeMet和亚硒酸盐的代谢途径，采用了一种新的多元素稳定同位素示踪方法对MeSeCys进行了精确的示踪。雄性Wistar大鼠以单一的80se富集同位素富集内源性天然丰度硒，然后以25 μg Se/kg体重同时口服76se - mesecys、77Se-SeMet和82se -硒酸盐。分别于3、6、9、12 h和1、2 d取器官和体液，进行物种形成分析。代谢的主要特征有：MeSeCys在硒蛋白P中的掺入量略高于或与SeMet相当，但低于亚硒酸盐。完整形态的器官吸收亚硒酸盐，但不吸收亚硒酸盐。MeSeCys和SeMet以一种与相同或相似的蛋白质结合的形式特异性地递送到胰腺。三甲基硒（TMSe）仅由MeSeCys产生，而不是由肾脏中的SeMet或亚硒酸盐产生。MeSeCys的硒糖A和B、SeMet和亚硒酸盐来源均在肝脏中检测到，而硒糖B仅在肾脏中检测到。这些结果表明，MeSeCys可能是与SeMet相似或更好的硒源，并且比SeMet和亚硒酸盐更有效地在器官中提供甲基硒醇。与SeMet和亚硒酸盐相比，MeSeCys产生TMSe的效率更高，这表明甲基硒醇通过β-裂解酶反应参与硒甲基化硒氨基酸的代谢。
Se-Methylated selenoamino acids, Se-methylselenocysteine (MeSeCys) and selenomethionine (SeMet), are chemically inert storage forms of selenium in selenium-accumulators, and a nutritional and supplemental source. The metabolic pathway for MeSeCys was precisely traced by referring to those for SeMet and selenite by applying a new tracer method involving multiple homo-elemental stable isotopes. Male Wistar rats were depleted of endogenous natural abundance selenium with a single80Se-enriched isotope, and then76Se-MeSeCys,77Se-SeMet and82Se-selenite were orally administered simultaneously at 25 μg Se/kg body weight each. Organs and body fluids were obtained at 3, 6, 9 and 12 h, and 1 and 2 days later, and subjected to speciation analysis. The main characteristics of the metabolism were as follows; MeSeCys was incorporated into selenoprotein P slightly more than or at a comparable level to that of SeMet but less than that of selenite. MeSeCys and SeMet but not selenite was taken up by organs in their intact forms. MeSeCys and SeMet were delivered specifically to the pancreas and present in a form bound to an identical or similar protein. Trimethylselenonium (TMSe) was only produced from MeSeCys, i.e., not from SeMet or selenite, in the kidneys. Both selenosugars A and B of MeSeCys, SeMet and selenite origin were detected in the liver but only selenosugar B in the kidneys. These results suggest that MeSeCys can be a similar or better selenium source than SeMet, and supplies methylselenol much more efficiently in organs than SeMet and selenite. TMSe was produced much efficiently from MeSeCys than from SeMet and selenite, suggesting a role of methylselenol through the β-lyase reaction in the metabolism of Se-methylated selenoamino acids.