INCREASE OF THE ANION AND PROTON PERMEABILITY OF SACCHAROMYCES-CARLSBERGENSIS PLASMALEMMA BY NORMAL-ALCOHOLS AS A POSSIBLE CAUSE OF ITS DEENERGIZATION

The effect on n‐alcohols on ATP‐dependent generation of ΔpH and Em across the plasma membrane vesicles of the yeast Saccharomyces carlsbergenesis was investigated. The alcohols were shown to collapse ΔpH and Em in the order C2<C3<C4<C5≤C6≥C7>C8>C11, the dissipation of Em being more pronounced. Inhibition of the plasmalemma H+‐ATPase was insignificannt: at low alcohol concentrations its activity even increased. The basic reason for the toxic effect of the alcohols on the yeast cells was suggested to be due to the increase in the anion and proton permeability of the plasma membrane. Mg2+ partially prevented the increase in the plasmalemma ion permeability by the alcohols investigated. Copyright © 1990 John Wiley & Sons Ltd.