Kosterin S A, Bratkova N F, Slinchenko N N, Zimina V P
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kiev, Ukraine.
Biofizika. 1998 Nov-Dec;43(6):1037-42.
It was shown that organic solvents (dioxane, acetone, ethanol, dimethylsulfoxide) at concentrations of < 10% suppress the activity of transport Ca2+, Mg(2+)-ATPase solubilized from plasmatic membranes of smooth muscle cells and Mg(2+)-ATP-dependent accumulation of Ca2+ ions in inverted membrane vesicles. It was found that one of the reasons for the inhibition of enzymatic and transport activity of Ca2+, Mg(2+)-ATPase by the action of these solvents is an increase in the attractive force between oppositely charged active center of the enzyme and the product (products) of the ATP-hydrolase reaction, which is induced by a decrease in the dielectric permeability of incubation medium.
结果表明，浓度低于10%的有机溶剂（二氧六环、丙酮、乙醇、二甲基亚砜）可抑制从平滑肌细胞质膜溶解的转运Ca2+、Mg(2+)-ATP酶的活性，以及Ca2+离子在反向膜囊泡中的Mg(2+)-ATP依赖性积累。研究发现，这些溶剂抑制Ca2+、Mg(2+)-ATP酶的酶活性和转运活性的原因之一是，孵育介质介电常数降低导致酶的带相反电荷的活性中心与ATP水解酶反应产物之间的吸引力增加。
