Effect of ethanol on alkaline phosphatase activity in HeLa cells

Incubation of HeLa cells with 10-80 mM ethanol, caused a dose-dependent decrease in alkaline phosphatase specific activity. With 80 mM ethanol, the decrease became apparent after 24-48 hr incubation. The same dose-dependent effect was observed with the nonmetabolizable alcohol t-butanol. The effect of ethanol was not due to toxicity as the cells continued to replicate for weeks in the presence of ethanol and was reversible. There were no differences in the Km values of alkaline phosphatase in crude extracts or solubilized enzyme prepared either from control or 80 mM ethanol-treated cells. Hydrocortisone and choline chloride, which by themselves increase alkaline phosphatase specific activity, altered the effect of ethanol on alkaline phosphatase. In the presence of either 1 microM hydrocortisone or 40 mM choline chloride, neither 10 nor 20 mM ethanol decreased alkaline phosphatase specific activity.