Plasma selenium in specific and non-specific forms
Plasma selenium in specific and non-specific forms
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DOI：
10.1002/biof.5520140115
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发表时间：
2001-01-01
期刊：
影响因子：
6
通讯作者：
Motley, AK
中科院分区：
文献类型：
--
作者：
Burk, RF;Hill, KE;Motley, AK
硒以特异性和非特异性形式存在于血浆和组织中。本文报道的实验是为了阐明影响等离子体中这些形式元素的一些因素。在另一项单独的实验中，研究人员每天以硒代蛋氨酸和硒酸盐的形式服用400杯硒，持续28天。硒代蛋氨酸提高血浆和白蛋白硒浓度。硒酸盐没有。在基础和硒补充条件下，白蛋白中蛋氨酸与硒的摩尔比约为8000，而添加硒代蛋氨酸后的摩尔比约为2800。这表明来自硒代蛋氨酸的硒，而不是来自硒酸盐的硒，可以被纳入白蛋白中，可能是蛋氨酸池中的硒代蛋氨酸。用硒-75-硒半胱氨酸研究了大鼠体内硒半胱氨酸与白蛋白的结合。没有证据表明硒-75在外源性给药或硒-75-硒半胱氨酸内源性合成后进入白蛋白。因此，硒代半胱氨酸似乎不像硒代蛋氨酸那样非特异性地结合到蛋白质中。这些发现支持硒代蛋氨酸是硒的一种非特异性形式，它作为蛋氨酸池的组成部分被代谢，不受特定硒代谢过程的影响。当硒作为硒酸盐或硒半胱氨酸给药时，没有发现硒非特异性掺入血浆蛋白的证据。这些形式的元素似乎通过特定的硒代谢过程代谢。
Selenium is present in plasma and tissues in specific and non-specific forms. The experiments reported here were carried out to clarify some factors that affect these forms of the element in plasma. A selenium-replete human subject was given 400 mug of selenium daily for 28 days as selenomethionine and, in a separate experiment, as selenate. The selenomethionine raised plasma and albumin selenium concentrations. Selenate did neither. The molar ratio of methionine to selenium in albumin was approximately 8000 under basal and selenate-supplemented conditions but 2800 after selenomethionine supplementation. This demonstrates that selenium from selenomethionine, but not selenium from selenate, can be incorporated into albumin, presumably as selenomethionine in the methionine pool. Selenocysteine incorporation into albumin was studied in rats using Se-75-selenocysteine. No evidence was obtained for incorporation of Se-75 into albumin after exogenous administration or endogenous synthesis of Se-75-selenocysteine. Thus, selenocysteine does not appear to be incorporated non-specifically into proteins as is selenomethionine. These findings are in support of selenomethionine being a non-specific form of selenium that is metabolized as a constituent of the methionine pool and is unaffected by specific selenium metabolic processes. No evidence was found for non-specific incorporation of selenium into plasma proteins when it was administered as selenate or as selenocysteine. These forms of the element appear to be metabolized by specific selenium metabolic processes.