The mechanism of action of dimethyllaurylbenzylammonium chloride (Ajatin) on rough and smooth forms of yeast cells

Abstract

It was found that Ajatin considerably inhibited the consumption of oxygen by rough and smooth forms of yeast cells utilizing glucose, the effect being apparent at concentrations much lower than those which would damage the cell wall. The rough forms of yeast cells are much more sensitive to this influence of Ajatin than the smooth ones. At higher concentrations of Ajatin no increase in enzyme activity can be observed, which contrasts with the finding of an increased dehydrogenation activity caused by Ajatin under anaerobic conditions and which indicates a higher sensitivity of respiration to Ajatin. A sublethal concentration of Ajatin (1 mg.%) brought about a mild stimulation of oxygen consumption by the smooth form 8—12%). The biochemical differences between the rough and smooth forms of yeasts, known from the literature, such as inactivation of thiol groups and a defect of the enzyme system in the action of flavoproteins, cannot account for the higher sensitivity of the rough forms to Ajatin. Of the enzyme inhibitors tested (sodiump-chloromercuribenzoate, sodium pyrophosphate and iodoacetic acid), only iodoacetic acid contributed markedly to the inhibitory effect of Ajatin, particularly in the smooth form, although it did not affect oxygen consumption by yeast cells utilizing glucose, when applied alone.