Interactions of lectins with (Na+ + K+)-ATPase of eel electric organ.

Interaction of lectins with a detergent-solubilized ATPase from eel electric organ was studied. Concanavalin A, which binds to alpha-mannosides, altered the rate of enzyme migration in agar and inhibited the formation of an antigen-antibody precipitate: other lectins had no such effects. Concanavalin A similar amounts partially inhibited (Na+ + K+)-ATPase; this inhibition was reversible by alpha-methylglucoside. There was no corresponding effect of concanavalin A on the potassium p-nitrophenylphosphatase. Concanavalin A also did not interfere with ouabain binding. Thus, concanavalin A binds to an antigenic region also involved in Na+ and/or ATP binding, but does not interact with a K+ site.