Inhibition of chloroplast coupling factor ATPase by 5′-p-fluorosulfonylbenzoyl adenosine

Abstract

Incubation of chloroplast coupling factor with 5′-p-fluorosulfonylbenzoyl adenosine in the 1 to 2 mM range inhibits subsequently measured ATPase activity. The inhibition is probably due to covalent binding since it survives ammonium sulfate fractionation and dialysis. The kinetics of the inhibited enzyme with respect to substrate show a decrease in V max with no change in K m for ATP. The presence of ATP or ADP together with the inhibitor provides some protection against inhibition. The results suggest a possible covalent attack at a nucleotide binding site, leading to inhibition of activity.