连续监测法测定血清亮氨酸氨基肽酶的活性及临床应用

目的应用亮氨酰对硝基苯胺(Leu-pNA)为底物建立测定血清亮氨酸氨基肽酶(LAP)活性的连续监测法,并探讨其在肝病诊断中的临床意义。方法基于LAP催化水解Leu-pNA生成有色对硝基苯胺的原理,对pH值、底物浓度、反应时间等条件进行研究,并用该法检测临床各种肝病血清LAP活性。结果酶促反应最适pH为7.20,最适底物浓度为4.8 mmol/L,批内、批间平均变异(CV%)分别为3.68%、5.91%。临床检验表明,肝硬化、活动性肝炎患者的血清LAP活性均高于正常组,呈现显著性差异(P<0.05)。结论本法灵敏度高,结果准确,且操作简便,在肝脏疾病诊断中具有临床意义。

Continuous Monitoring Assay for Leucine Aminopeptidase in Serum and Its Clinical Value

Objective To establish the continuous monitoring method for serum leucine aminopeptidase （LAP） activity using the substrate leucyl-p- nitroaniline （Leu-pNA） , and explore its clinical value in diagnosis of the liver diseases. Methods Based on the generation of color substance upon hydrolysis of the substrate into p-nitroanilin, we have studied the pH value, the substrate concentration and the reaction time et al. The serum LAP activities in different liver patients were determined by this spectrophotometric method. Results The enzyme optimum pH was 7.20, the optimal substrate concentration was 4.8 mmol/L, and the within-run and between-run CVs ranged from 3.68 to 5.91%. The serum LAP activities in patients with cirrhosis and active hepatitis were higher than the normal group, and there were significant differences compared with normal group （P〈0.05） . Conclusion Its sensitivity, precision and simplicity make the proposed method very suitable for diagnosing of different liver diseases in clinics.