AMP impairs ANT functioning by competing with the ADP binding site. A, effect of AMP on ADP-dependent ATP production by isolated mitochondria. B, effect of increasing ADP concentrations on AMP-dependent inhibition of mitochondrial ATP production. CRL, control. C, effect of ATR (100 μm) or AMP on binding of [14C]ADP to mitochondria (inset, saturation curve). D, effect of AMP on mitochondrial ADP uptake and ATP output; inset, the effect of AMP is not additive to that of ATR. Bars/points represent the mean ± S.E. of at least three experiments conducted in duplicate.