Clery C, Bec N, Balny C, Mozhaev V V, Masson P
Service de Santé des Armées Emile Pardé, Unité de Biochimie, La Tronche, France.
Biochim Biophys Acta. 1995 Nov 15;1253(1):85-93. doi: 10.1016/0167-4838(95)00137-j.
The combined effects of high pressure and reversed micelles have been studied to modulate the catalytic behaviour of butyrylcholinesterase. The purpose of this study was to determine whether the conformational plasticity of the enzyme is altered by entrapment in reversed micelles. The presence of soman, an irreversible inhibitor of cholinesterase was used to bring to the fore a possible modification of the enzyme behaviour in this system under pressure. Results show differences between enzyme in conventional medium and in reversed micelles regarding the mechanism of BuChE catalyzed hydrolysis of acetylthiocholine. In both systems, the enzyme displays a non-Michaelian behaviour with this substrate. In conventional medium the kinetics is multiphasic with an activation phase followed by an inhibition phase at high concentration. In reversed micelles there is inhibition by excess substrate but the activation phase is missing. This behaviour may be the result of a change of the enzyme conformational plasticity when is entrapped in reversed micelles.
研究了高压和反胶束的联合作用对丁酰胆碱酯酶催化行为的调节。本研究的目的是确定酶的构象可塑性是否会因被困在反胶束中而改变。使用胆碱酯酶的不可逆抑制剂梭曼来突出该系统中压力下酶行为的可能变化。结果表明，在丁酰胆碱酯酶催化乙酰硫代胆碱水解的机制方面，传统介质中的酶与反胶束中的酶存在差异。在这两个系统中，该酶对这种底物均表现出非米氏行为。在传统介质中，动力学是多相的，在高浓度时先有一个激活阶段，随后是一个抑制阶段。在反胶束中，存在过量底物的抑制作用，但缺少激活阶段。这种行为可能是酶被困在反胶束中时构象可塑性发生变化的结果。
