The effects of methanol, butanol, glycerol, glucose, sucrose and inorganic anions on the activity of soluble ATPase from mouse liver mitochondria were studied. Glycerol inhibited, while methanol stimulated the enzyme activity uncompetitively with respect to ATP and competitively with respect to each other. Glycerol-induced inhibition of ATPase was competitive with respect to sulphite; methanol competed with thiocyanate for the enzyme activity. The Arrhenius plots for ATPase revealed bends at 20 degrees and 30 degrees C in the presence of sulphite, chlorine, thiocyanate, glycerol and methanol. It was assumed that all the compounds tested influenced soluble ATPase by changing the nucleophilic activity of H2O.