Li P K, Shull B C
Clin Chem. 1979 Apr;25(4):611-3.
We describe a fixed-time, enzymatic, reaction-rate procedure for determining plasma ammonia with a centrifugal analyzer (Rotochem IIA/36; American Instrument Co., silver Spring, MD 20910), with NADPH as cofactor. The reaction is based on that of da Fonseca-Wollheim's modification [J. Clin. Chem. Clin. Biochem. 11, 421 (1973)] of the Kirstein reaction, which depends on the catalytic amination of alpha-ketoglutarate by the action of glutamate dehydrogenase with NADPH as the cofactor instead of NADH. Use of NADPH minimizes interference from endogenous reactions such as that between lactate dehydrogenase and pyruvate. This method permits shortened preincubation time and thus improves both specificity and precision. This assay requires 100 microliter of freshly collected heparinized plasma, gives quantitative analytical recovery, and the standard curve is linear to 430 mumol/L. Data are presented comparing results with those by two other enzymatic ammonia procedures.
我们描述了一种使用离心分析仪（Rotochem IIA/36；美国仪器公司，马里兰州银泉市20910），以NADPH为辅酶，通过固定时间的酶促反应速率法来测定血浆氨的方法。该反应基于达·丰塞卡 - 沃尔海姆对基尔施泰因反应的改进[《临床化学与临床生物化学杂志》11, 421 (1973)]，其依赖于谷氨酸脱氢酶以NADPH而非NADH作为辅酶作用于α-酮戊二酸的催化胺化反应。使用NADPH可最大程度减少内源性反应（如乳酸脱氢酶与丙酮酸之间的反应）的干扰。该方法可缩短预孵育时间，从而提高特异性和精密度。此检测方法需要100微升新鲜采集的肝素化血浆，具有定量分析回收率，标准曲线在430微摩尔/升范围内呈线性。文中给出了将该方法的结果与另外两种酶促氨检测方法的结果进行比较的数据。
