Blocking one non-catalytic ADP binding site results in complete inhibition of the F-type ATPase from the thermophilic Bacillus PS3

The F-type ATPase, TF₀F₁, from the thermophilic Bacillus PS3, which is free of nucleotides after isolation, was specifically loaded with one 2-azido ADP on a non-catalytic site. The enzyme was covalently modified to various extents and the rate of ATP synthesis and ATP hydrolysis was measured. Both ATP synthesis and ATP hydrolysis extrapolated to zero for covalentiy binding one nucleotide per enzyme. This was interpreted such that the non-catalytic sites are involved in the coupled catalytic process.