The effect of pH on the toxicity of fluoroacetic acid

Abstract

When yeast cells are exposed to high concentrations of fluoroacetic acid (HFA) in the presence of glucose, the loss in viability which results is proportional to the concentration of undissociated HFA. Inhibition of O2 consumption which is complete at much lower concentrations of HFA is likewise dependent upon the amount of undissociated HFA in the cell''s environment. Inhibition of O2 consumption is only partially reversed by washing with buffer of the same pH as that at which the cells were exposed to the HFA; this fact suggests that the ultimate inhibitory agent is some non-diffusible metabolite of HFA. Inhibition of O2 consumption is pH-labile, which indicates either that the inhibitory agent is dissociable or that the metabolic reactions of the cell change with variation in environmental pH.