Effect of Detergents on Activity and Magnesium-Dependent Properties of Different Isoforms of [Na.sup.+],[K.sup.+]-ATPase in the Crude Membrane Fraction of Rat Cerebral Cortex

We studied the effect of various detergents (Tween-20, Triton X-100, and sodium deoxycholate) on activity and magnesium-dependent properties of [Na.sup.+],[K.sup.+]-ATPase of the crude membrane fraction of rat cerebral cortex. All studied detergents significantly increased activity of the studied enzyme in a concentration-dependent manner. Sodium deoxycholate provided significantly higher values [Na.sup.+],[K.sup.+]-ATPase activity (by [approximately equal to]50%) than Triton X-100 and Tween-20. In the presence of Triton X-100, a changed pattern of the dependence of enzyme activity on the concentration of magnesium ions in the incubation solution was noted. Separate measurement of activities of [Na.sup.+],[K.sup.+]-ATPase isoforms made it possible to assume that changes in magnesium-dependent properties are due to the predominant effect of Triton X-100 on ouabain-sensitive [alpha]2- and [alpha]3-isoforms. Key Words: [Na.sup.+],[K.sup.+]-ATPase; Triton X-100; Tween-20; sodium deoxycholate