[Stimulation mechanism of soluble ATPase from chloroplasts (CF1)]

Effects of various compounds on Mg-dependent ATPase activity of chloroplast coupling factor--CF1--were studied. It was shown that the stimulating effect of compounds is increased with the increase in their hydrophobicity. Under given experimental conditions all compounds under study readily accept and donate protons. The maximal efficiency is reached when pH of the medium is close to the pK value of conjugated acid. It is assumed that the stimulating effects of compounds on Mg-dependent chloroplast ATPase consist in the increase of the rate of the limiting step of enzyme induced proton translocation coupled to the catalytic step of ATP hydrolysis.