[Sensitivity of rat brain Na+,K+-ATPase catalytic subunit isoforms to Ds-Na]

Analysis of the detergent effect on the dose response curve of ouabain inhibition of rat brain Na+,K(+)-ATPase revealed that the microsomal alpha(+)-isoform was more stable to inactivation by SDS than the alpha-isoform of Na+,K(+)-ATPase from brain cortex and renal outer medulla. Data from SDS-PAAG electrophoresis of membrane-bound Na+,K(+)-ATPase suggest that irreversible inactivation of the isozymes is accompanied by their removal from the membrane but the alpha-isoform is more sensitive to the solubilizing effect of SDS.