Effect of organic solvents on catalytic and functional activity of transport Ca2+,Mg2+-ATPase of plasmatic membranes of smooth muscle cells

It; was shown that organic solvents (dioxane, acetone, ethanol, dimethylsul foxide) at concentrations of < 10% suppress the activity of transport Ca2+, Mg2+-ATPase solubilized from plasmatic membranes of smooth muscle cells an d Mg2+-ATP-dependent accumulation of Ca2+ ions in inverted membrane vesicle s. It. was found that one of the reasons for the inhibition of enzymatic an d transport: activity of Ca2+, Mg2+-ATPase by the action of these solvents is an increase in the attractive force between oppositely charged active ce nter of the enzyme and the product (products) of the ATP-hydrolase reaction , which is induced by a decrease in the dielectric permeability of incubati on medium.