Kanda S, Sudo K, Kanno T
Clin Chem. 1984 Jun;30(6):843-6.
This is a method for measuring tripeptide aminopeptidase (EC 3.4.11.4) activity in serum. L- Leucylglycylglycine is used as substrate, and the reaction is followed by monitoring the absorbance increase at 340 nm when NAD+ is reduced to NADH in the presence of an excess of leucine dehydrogenase. This principle allows kinetic determination of the enzyme without interference by carboxypeptidases. Amastatin is added to the reaction mixture to prevent nonspecific hydrolysis of the substrate catalyzed by other aminopeptidases. As final reaction concentrations we recommend (per liter): 100 mmol of Tris buffer (pH 8.2), 4.0 mmol of L- leucylglycylglycine , 10 kU of leucine dehydrogenase, 3.8 mmol of NAD+, and 85 mumol of amastatin . The assay is suited to modern enzyme analyzers and has high precision.
这是一种测定血清中三肽氨基肽酶（EC 3.4.11.4）活性的方法。以L-亮氨酰甘氨酰甘氨酸作为底物，在过量亮氨酸脱氢酶存在的情况下，当NAD⁺还原为NADH时，通过监测340 nm处吸光度的增加来跟踪反应。该原理可实现酶的动力学测定，而不受羧肽酶的干扰。向反应混合物中加入抑肽酶，以防止其他氨基肽酶催化底物的非特异性水解。作为最终反应浓度，我们推荐（每升）：100 mmol Tris缓冲液（pH 8.2）、4.0 mmol L-亮氨酰甘氨酰甘氨酸、10 kU亮氨酸脱氢酶、3.8 mmol NAD⁺和85 μmol抑肽酶。该测定法适用于现代酶分析仪，且具有高精度。
