INACTIVATION OF THE BRAIN NA-ATPASE C ATALYTIC SUBUNIT ISOFORMS BY SODIUM DODECYL-SULFATE(,K+)

The comparative study of the stabilities to SDS inactivation of the br ain and kidney Na+,K+-ATPase isozymes under different time and tempera ture conditions of the microsome extraction with the detergent was con ducted. In contrast to the enzyme preparations from medulla oblongata the higher sensitivity of the Na+,K+-ATPase alpha-isoform (in comparis on to alpha(+)) to SDS inactivation accompanied by its, at least, part ial removal from the membrane was found in the preparations from cereb ral cortex, This difference in the sensitivity to SDS are eliminated a fter extraction of microsomes with the detergent at 37 degrees C. The results interpretation is based on the assumption on the existence of differences in structural organization of the boundary lipids of the n euronal Na+,K+-ATPase catalytic subunit isoforms.