仅使用一种酶——异柠檬酸脱氢酶（NADP⁺）测定血清和尿液中的镁。

Assay of magnesium in serum and urine with use of only one enzyme, isocitrate dehydrogenase (NADP+).

作者信息

Fujita T, Kawakami Y, Kohda S, Takata S, Sunahara Y, Arisue K

机构信息

Biochemical Research and Development Center, Oriental Yeast Co., Osaka, Japan.

出版信息

Clin Chem. 1995 Sep;41(9):1302-5.

PMID:7656441

Abstract

We report a method for assaying magnesium in serum and urine involving only one enzyme, isocitrate dehydrogenase (NADP+)(EC 1.1.1.42), which requires magnesium ion for activity. The enzymatic reduction of NADP+ by isocitrate increases in rate linearly up to at least 20 mmol/L magnesium in the presence of appropriate concentrations of the two metal-chelating reagents, EDTA and glycol ether diamine-N,N,N',N'-tetraacetate. Within-run (n = 20) CVs and day-to-day (n = 10) CVs for sera are < or = 1.5% and < or = 2.6%, respectively. Analytical recovery of magnesium in sera averages 96-100%. This method is not affected by bilirubin, hemoglobin, or lipemia. The method (y) gives the following results correlating with atomic absorption spectrophotometry (x): y = 1.03x + 0.06 mmol/L (n = 62, r = 0.995, Sylx = 0.03) for sera, and y = 1.03x - 0.10 mmol/L (n = 62, r = 0.989, Sylx = 0.19) for urines; with the calmagite method (x): y = 0.99x + 0.04 mmol/L (n = 62, r = 0.991, Sylx = 0.03) for sera, and y = 0.98x + 0.03 mmol/L (n = 62, r = 0.999, Sylx = 0.02) for urines.

摘要

我们报告了一种仅涉及一种酶（异柠檬酸脱氢酶（NADP⁺），EC 1.1.1.42）的血清和尿液中镁含量测定方法，该酶的活性需要镁离子。在适当浓度的两种金属螯合剂乙二胺四乙酸（EDTA）和乙二醇醚二胺 - N，N，N'，N'-四乙酸存在的情况下，异柠檬酸对NADP⁺的酶促还原速率在镁浓度至少达到20 mmol/L时呈线性增加。血清批内（n = 20）变异系数（CV）和日间（n = 10）CV分别≤1.5%和≤2.6%。血清中镁的分析回收率平均为96 - 100%。该方法不受胆红素、血红蛋白或脂血的影响。该方法（y）与原子吸收分光光度法（x）的相关性结果如下：血清中y = 1.03x + 0.06 mmol/L（n = 62，r = 0.995，Sylx = 0.03），尿液中y = 1.03x - 0.10 mmol/L（n = 62，r = 0.989，Sylx = 0.19）；与钙镁试剂法（x）的相关性结果如下：血清中y = 0.99x + 0.04 mmol/L（n = 62，r = 0.991，Sylx = 0.03），尿液中y = 0.98x + 0.03 mmol/L（n = 62，r = 0.999，Sylx = 0.02）。