Colombi A, Maroni M, Antonini C, Cassina T, Gambini A, Foà V
Clin Chim Acta. 1983 Mar 14;128(2-3):337-47. doi: 10.1016/0009-8981(83)90333-9.
The enzymatic methods for measuring D-glucaric acid in urine are based on the conversion of D-glucaric acid into its 1,4-lactone and measurement of inhibition of 1,4-lactone against beta-glucuronidase at pH 5.0. All the enzymatic methods described suffer from the disadvantage of a procedure that is complicated and inherently inaccurate, because the nature of glucaric acid/1,4-lactone equilibrium has not been properly considered in the development of such methods. After elucidating the factors influencing glucaric acid/1,4 lactone equilibrium in more detail, a low-pH enzymatic method has been developed in which the 1,4-lactone is formed in the urine sample by acid boiling at pH 3.8 and assayed at the same pH using beta-glucuronidase from Limpets. This procedure allows the acid/lactone equilibrium to remain stable during both the lactonization step and the enzymatic assay. The coefficient of variation for the proposed method (within-run and between-day precision) was from 4.2 to 8.7. The analytical recovery varied from 92-108%.
尿液中D - 葡糖二酸的酶法测定基于D - 葡糖二酸转化为其1,4 - 内酯，并在pH 5.0条件下测定1,4 - 内酯对β - 葡糖醛酸酶的抑制作用。所描述的所有酶法都存在操作复杂且本质上不准确的缺点，因为在开发此类方法时未充分考虑葡糖二酸/1,4 - 内酯平衡的性质。在更详细地阐明影响葡糖二酸/1,4 - 内酯平衡的因素后，开发了一种低pH酶法，其中通过在pH 3.8下酸煮在尿液样本中形成1,4 - 内酯，并使用帽贝中的β - 葡糖醛酸酶在相同pH下进行测定。该程序可使酸/内酯平衡在内酯化步骤和酶法测定过程中保持稳定。所提出方法的变异系数（批内和批间精密度）为4.2%至8.7%。分析回收率在92%至108%之间。
