Na/K-ATPase as an oligomeric ensemble

Differences in the kinetic behavior and properties of monomeric and oligome ric, forms of membrane-bound Na/K-ATPase are analyzed. It is concluded that enzyme molecules within oligomeric complexes are affected by extrinsic sig nals that result in change of enzyme activity, whereas the individual (prot omeric) state is insensitive to these signals. Some of the major factors of such regulation are microviscosity of the lipid environment, reactive oxyg en species, and intracellular protein kinases.