[Interaction of alkaline phosphatase and acid phospholipids in E. coli cells and artificial membranes]

The synthesis of alkaline phosphatase, an enzyme secreted by E. coli, is decreased in the cells pretreated with the lipotropic antibiotic polymixin prior to derepression. The decrease of the enzyme synthesis in the cell is correlated with the changes in the intracellular and intramembrane ratios of acid phospholipids, presumably at the level of the cytoplasmic membrane. The interaction between alkaline phosphatase and artificial lipid membranes has been shown to be a function of pH and ionic strength and is increased in the liposomes rich in acid phospholipids and decreased in the polymixin-treated liposomes.