Mullins R E, Miller R L, Hunter R L, Bennett B
Clin Chem. 1984 Nov;30(11):1857-60.
We describe an enzymic assay for the functional activity of alpha 1-antitrypsin, in which tosyl-Gly-Pro-Lys-p-nitroanilide acetate (Chromozym PL) is the trypsin substrate. For the indicating reaction, the concentration of substrate is about double the Km of its reaction with trypsin. This assay is an improvement over reactions involving N-alpha-benzoyl-DL-arginine p-nitroanilide as substrate, the solubility of which in water is less than the Km of its reaction with trypsin. The assay is standardized in terms of active sites of trypsin inhibited per liter of serum, with p-nitrophenyl-p'-guanidinobenzoate as the active site titrant. The results agreed well with those by an immunonephelometric assay for alpha 1-antitrypsin (r = 0.953). The within-run and run-to-run precision was approximately 3%. The results of the assay varied linearly with alpha 1-antitrypsin concentration from 0 to 60 mumol/L of serum. The minimum sample size was 50 microL, and analysis of 24 samples took less than 20 min.
我们描述了一种用于检测α1-抗胰蛋白酶功能活性的酶法测定方法，其中甲苯磺酰甘氨酰-脯氨酰-赖氨酰-对硝基苯胺乙酸盐（Chromozym PL）是胰蛋白酶的底物。对于指示反应，底物浓度约为其与胰蛋白酶反应的Km值的两倍。该测定方法是对以N-α-苯甲酰-DL-精氨酸对硝基苯胺为底物的反应的改进，后者在水中的溶解度低于其与胰蛋白酶反应的Km值。该测定方法以每升血清中被抑制的胰蛋白酶活性位点为标准，以对硝基苯基-p'-胍基苯甲酸酯作为活性位点滴定剂。结果与α1-抗胰蛋白酶免疫比浊法的结果高度一致（r = 0.953）。批内和批间精密度约为3%。该测定结果与血清中α1-抗胰蛋白酶浓度在0至60μmol/L范围内呈线性变化。最小样本量为50μL，分析24个样本耗时不到20分钟。
