血管紧张肽（素）转化酶动力学测定方法的探讨及其初步临床应用

目的建立血管紧张肽（素）转化酶（ACE）自动化分析方法。方法 ACE能催化底物呋喃酰基-L-苯丙氨酰甘氨酰甘氨酸（FAPGG）,产生呋喃酰基苯丙氨酸（FAP）及双甘氨肽（GG）。在pH值8.2的硼酸缓冲液下,在340 nm处测定产物吸光度值的下降速度可计算出ACE活性。采用本法测定50名正常对照者、30例慢性阻塞性肺部疾病加重期（AECOPD）患者、18例肺癌患者血清ACE的活性。结果本法缓冲液最适pH值为8.2,最适基质浓度为1.0 mmol/L,批内、批间平均变异系数（CV）分别为4.07%、5.50%,米氏常数（Km）为0.09 mmol/L。正常对照组ACE活性为（31.1±18.0）U/L;AECOPD患者ACE活性为（22.4±12.6）U/L,低于正常组（P〈0.000 1）;肺癌患者ACE活性为（28.7±11.4）U/L,稍低于正常对照组,但差异无统计学意义（P〉0.05）。结论该法简便、快捷、精确,可用于自动化分析,适宜临床常规应用。ACE可作为评价肺部疾病的一项指标。

Investigation on kinetic monitoring of angiotensin converting enzyme and its preliminary clinical application

Objective To establish a kinetic monitoring assay for detecting angiotensin converting enzyme（ACE）.Methods N-（32-Furyl]Acryloyl）-L-Phe-Gly-Gly（FAPGG） was used as substrate.ACE could catalyze the substrate to produce N-（32-Furyl]Acryloyl）-L-Phe（FAP） and glycine-glycine（GG） in boric acid-sodium hydroxide buffer（pH： 8.2）.The activity of ACE could be calculated through determining the decreasing speed of the product at 340 nm.The ACE activities in 50 healthy controls,30 patients with acute exacerbation chronic obstructive pulmonary disease（AECOPD） and 18 patients with lung cancer were determined by this method.Results The optimum pH value of the buffer was 8.2,and the optimum substrate concentration was 1.0 mmol/L.The within-run coefficient of variation（CV） was 4.07%,and between-run CV was 5.50%.Michaelis constant（Km） was 0.09 mmol/L.The ACE activities were（31.1±18.0）U/L in healthy controls and（22.4±12.6）U/L in patients with AECOPD.There was a significant difference between AECOPD patients and healthy controls（P〈0.000 1）.The ACE activity in patients with lung cancer was（28.7±11.4） U/L.It was slightly lower than that in the healthy controls,and there was no statistical significance between patients with lung cancer and healthy subjects（P〈0.05）.Conclusions The method is simple,rapid,accurate and suitable for automatic analysis of ACE.The method can be used for clinical application,and ACE can be an indicator for the evaluation of lung disease.