Friedland J, Silverstein E
Am J Clin Pathol. 1977 Aug;68(2):225-8. doi: 10.1093/ajcp/68.2.225.
A simple, rapid, highly sensitive and reproducible fluorimetric assay for angiotensin-converting enzyme in untreated serum using the natural substrate based on a similar assay with hippuryl-L-histidine-L-leucine is described. Angiotensin I (0.2 mM in 0.1 M potassium phosphate-30 mM NaCl, pH 7.5; 37 C) is converted to angiotensin II and L-histidyl-L-leucine, which is quantified fluorimetrically (excitation = 360 nm; fluorescence, 500 nm) by formation of a fluorescent adduct with O-phthaldialdehyde. L-Histidyl-L-leucine peptidase was also monitored in order to correct for significant activity, which was observed only once, in less than 1% sera. The mean value of serum angiotensin-converting enzyme in sera from 45 normal subjects was 4.69+/-0.194 (SEM)+/-1.30 (SD) nmol/min/ml serum, compared with 31.7+/-1.53 (SEM)+/-10.3(SD) with the substrate analog hippuryl-L-histidine-L-leucine. There was a high degree of correlation between the velocity of cleavage of angiotensin I and hippuryl-L-histidyl-L-leucine (r - 0.903 to 0.993). The assay of serum angiotensin-converting enzyme is of use in the diagnosis and possible management of sarcoidosis and Gaucher's disease, and may have other applications.
本文描述了一种基于马尿酰-L-组氨酸-L-亮氨酸的类似检测方法，用于在未经处理的血清中对血管紧张素转换酶进行简单、快速、高度灵敏且可重复的荧光检测。血管紧张素I（在0.1M磷酸钾-30mM氯化钠，pH7.5；37℃中为0.2mM）被转化为血管紧张素II和L-组氨酰-L-亮氨酸，后者通过与邻苯二甲醛形成荧光加合物进行荧光定量（激发波长=360nm；荧光波长，500nm）。还监测了L-组氨酰-L-亮氨酸肽酶，以校正显著活性，这种活性仅在不到1%的血清中观察到一次。45名正常受试者血清中血管紧张素转换酶的平均值为4.69±0.194（标准误）±1.30（标准差）nmol/分钟/毫升血清，而使用底物类似物马尿酰-L-组氨酸-L-亮氨酸时为31.7±1.53（标准误）±10.3（标准差）。血管紧张素I和马尿酰-L-组氨酰-L-亮氨酸的裂解速度之间存在高度相关性（r=0.903至0.993）。血清血管紧张素转换酶检测在结节病和戈谢病的诊断及可能的治疗中有用，且可能有其他应用。
