Kost O A, Ort T A, Nikol'skaia I I, Nametkin S N, Lebashov A V
Biokhimiia. 1994 Nov;59(11):1746-55.
Regulation of the catalytic activity and the supramolecular structure of the angiotensin-converting enzyme isolated from bovine lungs has been studied in a system of reversed micelles of aerosol OT (AOT) in octane. The curve for the dependence of the enzyme catalytic activity on the degree of the surfactant hydration (micellar size) has two maxima at the hydration degrees of [H2O]/[AOT] 27 and 31. Data from velocity sedimentation suggest that depending on the hydration degree, the angiotensin-converting enzyme occurs in the system of reversed micelles in both monomeric and dimeric forms, the latter being catalytically active. In contrast with aqueous media, in the reversed micelle system the angiotensin-converting enzyme does not require chloride anions for its catalytic activity. In the system of reversed micelles of AOT in octane the holoenzyme is stable, while the apoenzyme rapidly and irreversibly loses its activity. Under these conditions the apoenzyme shows an ability to incorporate the Zn2+ ions into the enzyme active center; however, only in the presence of a substrate or an inhibitor.
在辛烷中气溶胶OT（AOT）反胶束体系中，对从牛肺中分离出的血管紧张素转换酶的催化活性和超分子结构的调节进行了研究。酶催化活性对表面活性剂水合度（胶束大小）的依赖性曲线在水合度[H₂O]/[AOT]为27和31时出现两个最大值。速度沉降数据表明，根据水合度的不同，血管紧张素转换酶在反胶束体系中以单体和二聚体形式存在，后者具有催化活性。与水性介质不同，在反胶束体系中血管紧张素转换酶的催化活性不需要氯离子。在辛烷中AOT反胶束体系中全酶是稳定的，而脱辅基酶迅速且不可逆地失去其活性。在这些条件下，脱辅基酶显示出将Zn²⁺离子掺入酶活性中心的能力；然而，仅在存在底物或抑制剂的情况下。
