Lack of immunological cross reactivity between the transport enzymes (Na+ + K+)-ATPase and (K+ + H+)-ATPase.

Goat antisera against (Na+ + K+)-ATPase and its isolated subunits and against (K+ + H+)-ATPase have been prepared in order to test for immune cross-reactivity between the two enzymes, whose catalytic subunits show great chemical similarity. None of the (Na+ + K+)-ATPase antisera cross-reacted with (K+ + H+)-ATPase or inhibited its enzyme activity. The same was true for the (K+ + H+)-ATPase antiserum with regard to (Na+ + K+)-ATPase and its subunits and its enzyme activity. So notwithstanding the chemical similarity of their subunits, there is no immunological cross-reactivity between these two plasma membrane ATPases.