Binding of mitochondrial ATPase from ox heart to its naturally occurring inhibitor protein: localization by antibody binding.

The naturally occurring ATPase inhibitor protein from ox heart mitochondria was cross-linked to its binding site on the mitochondrial ATPase using 1-ethyl-3-(dimethylamino)propyl carbodiimide. The cross-linked product, when transferred electrophoretically to a nitrocellulose sheet, reacted with antibodies directed against the inhibitor protein and the beta-subunit of the ATPase. It was concluded that the binding site for the inhibitor protein lies on the beta-subunit.