Plasma Arginine Esterase in Cystic Fibrosis: Kinetics of Activation, Identification as Plasma Kallikrein, Reaction with μ2-Macroglobulin and Comparison with Levels in Normal Plasma
Plasma Arginine Esterase in Cystic Fibrosis: Kinetics of Activation, Identification as Plasma Kallikrein, Reaction with μ2-Macroglobulin and Comparison with Levels in Normal Plasma
复制标题
囊性纤维化中的血浆精氨酸酯酶：激活动力学、血浆激肽释放酶的鉴定、与 μ2-巨球蛋白的反应以及与正常血浆中水平的比较
作者：
A. F. Bury;A. J. Barrett
摘要：正常血浆经氯仿和花藻酸处理后，酯酶对tosylarginine methyl ester的活性在2 h内达到最大值，2 h后大部分或全部活性对大豆胰蛋白酶抑制剂（STI）的抑制具有抗性，但对低分子量抑制剂氟磷酸二异丙基、抑肽蛋白和脯氨苯丙酰精氨酸氯甲烷仍有敏感性。在μ2巨球蛋白（μ2M）凝胶层析层析中，活性表现为μ2M的蛋白酶复合物。氯仿和鞣花酸产生的精氨酸酯酶活性明显依赖于因子XII的激活，被聚苯醚阻断。用甲胺- hci （μ2M灭活剂）预处理的血浆中，精氨酸酯酶对STI抑制的敏感性为95%。在底物特异性、抑制特性和凝胶色谱行为方面，它与血浆钾激肽（EC 3.4.21.34，原3.4.21.8）无法区分。血浆中氯仿和鞣花酸处理导致原钾化酶消失，同时出现精氨酸酯酶。根据这些标准，精氨酸酯酶活性完全归因于血浆钾激肽的游离形式（甲胺处理的血浆）或结合μ2M（缓冲处理的血浆）。对囊性纤维化患者、专性杂合子或其他组血浆样品的精氨酸酯酶活性进行比较，发现活性水平、激活动力学或凝胶色谱行为没有显著差异。我们的结论是囊性纤维化与血浆精氨酸酯酶活性异常无关，这与以前的一些报道相反。
Summary: Treatment of normal plasma with chloroform and ellagic acid yielded esterase activity against tosylarginine methyl ester, which reached a maximum within 2 h. After 2 h most or all of the activity was resistant to inhibition by soybean trypsin inhibitor (STI), but was still sensitive to the low molecular weight inhibitors di-isopropyl fluorophosphate, aprotinin and prolyl-phenylalanyl-arginyl chloromethane. The activity ran in gel chromatography with μ2macroglobulin (μ2M), as if it were due to an μ2M proteinase complex.The generation of the arginine esterase activity by chloroform and ellagic acid was apparently dependent on the activation of factor XII, being blocked by Polybrene. In plasma pretreated with methylamine-HCI (an inactivator of μ2M), the arginine esterase was 95% sensitive to inhibition by STI. With regard to substrate specificity, inhibition characteristics, and gel chromatographic behaviour, it was indistinguishable from plasma kallikrein (EC 3.4.21.34, formerly 3.4.21.8). The chloroform and ellagic acid treatment of plasma resulted in a disappearance of prokallikrein simultaneous with the appearance of the arginine esterase. By these criteria, the arginine esterase activity was attributable entirely to plasma kallikrein either in its free form (methylamine-treated plasma) or bound to μ2M (buffer-treated plasma).Comparisons of STI-sensitive and STI-resistant arginine esterase activities of plasma samples from cystic fibrosis patients, obligate heterozygotes or other groups showed no significant differences in levels of activity, kinetics of activation or gel chromatographic behaviour.We conclude that cystic fibrosis is unrelated to any abnormality in plasma arginine esterase activity, contrary to some previous reports.