[Effect of organic solvents on catalytic and functional activity of transport Ca2+,Mg2+-ATPase from smooth muscle cell membrane].

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.