Lloyd C, Travis J
Athens Research and Technology, Inc., GA 30604.
Clin Chem. 1989 Sep;35(9):1971-5.
This rapid screening procedure for detection of low but functional elastase-inhibitory activity in human plasma is based on the fact that incubation of excess porcine pancreatic elastase (EC 3.4.21.36) with plasma results in formation of a complex with active alpha 1-proteinase inhibitor (alpha 1PI, also called alpha 1-antitrypsin). In normal individuals all of the elastase is complexed, leaving no free enzyme to hydrolyze the elastase substrate, and the reaction mixture remains clear. Because individuals homozygous for the Z allele have relatively low concentrations of alpha 1PI, their plasma cannot complex all of the elastase in the assay. The uncomplexed enzyme hydrolyzes the elastase-specific p-nitroanilide substrate, producing a yellow reaction mixture. Use of this simple assay for early screening of individuals for alpha 1PI deficiency may substantially decrease the number of untreated cases of familial emphysema, a disorder that develops as a result of a genetically derived proteinase-proteinase inhibitor imbalance.
将过量的猪胰弹性蛋白酶（EC 3.4.21.36）与血浆一起孵育会导致与活性α1-蛋白酶抑制剂（α1PI，也称为α1-抗胰蛋白酶）形成复合物。在正常个体中，所有弹性蛋白酶都形成了复合物，没有游离酶来水解弹性蛋白酶底物，反应混合物保持澄清。由于Z等位基因纯合个体的α1PI浓度相对较低，他们的血浆在检测中无法使所有弹性蛋白酶都形成复合物。未形成复合物的酶会水解弹性蛋白酶特异性的对硝基苯胺底物，产生黄色反应混合物。使用这种简单的检测方法对个体进行α1PI缺乏的早期筛查，可能会大幅减少未治疗的家族性肺气肿病例数量，家族性肺气肿是一种由于遗传导致的蛋白酶-蛋白酶抑制剂失衡而发展的疾病。
