Ligand-induced variations in subunit associations in bovine heart F1 ATPase

Bovine heart soluble F1 ATPase shows ligand dependent changes in subunit accessibility to the protein labelling reagents acetic anhydride and diazonium benzenesulphonic acid. These correlate with changes in the ATPase activity of the enzyme induced by the same ligands. In particular, NAD+ and NADH show concentration dependent effects, the effect of the reduced nucleotide being opposite to that of the oxidised form.