EFFECT OF LIPID A AND FATTY ACIDS ON TRANSPORT ACTIVITIES OF MEMBRANE VESICLES FROM ESCHERICHIA COLI

Abstract

The effect of lipid A from Salmonella typhimurium and various fatty acids on the transport activities of membrane vesicles from Escherichia coli was investigated. It was found that lipid A and fatty acids severely inhibited the accumulation of succinate or serine which are coupled to the electron transport, while the transport of glucose, which was catalyzed by the phosphotransferase system, was stimulated slightly by these compounds. Lipid A and myristic acid appeared to act at the same site in the succinate transport system, since no additive effect was observed in the inhibition even at a low concentration of these compounds. Lipid A and myristic acid caused the efflux of pre-loaded ¹⁴C-succinate in the membrane vesicles.