Effect of cetyltrimethylammonium on ATP hydrolysis and proton translocation in the F0-F1 H+-ATP synthase of mitochondria.

The amphiphylic alkyl cation cetyltrimethylammonium inhibits the catalytic activity of soluble and membrane-bound F1 in a noncompetitive fashion. In sonic submitochondrial particles the Dixon plot showed a peculiar pattern with upward deviation at cetyltrimethylammonium concentration higher than 80 microM. In membrane-bound F1 the inhibition by cetyltrimethylammonium was potentiated by the F0 inhibitor ologomycin. Cetyltrimethylammonium also inhibited the oligomycin-sensitive proton conductivity in F1-containing particles but was without any effect in F1-depleted particles. Also this inhibitory effect was potentiated by oligomycin. These results indicate functional cooperative interactions between F0 and F1.