MECHANISM OF OXIDATIVE DAMAGE OF DOG KIDNEY NA K-ATPASE/

Oxidative modification of kidney Na/K-ATPase was found to be accompani ed by a decrease in the amount of sulfhydryl groups accessible for Elm ann reagent with subsequent transformation of kinetic behavior of the enzyme. Oxidation of Na/K-ATPase with 20 mM hydrogen peroxide during 2 0 min results in about 50% inhibition of its activity and subsequent t ransformation of complex substrate-velocity dependence into the simple hyperbolic curve. In terms of kinetic analysis the suggestion was mad e that partial oxidation of Na/K-ATPase by hydrogen peroxide results i n disordering of interprotomer interaction in the oligomeric complex o f Na/K-ATPase. (C) 1996 Academic Press, Inc.