Open AccessUncoupling Action of Amytal in Membrane Vesicles from Escherichia coli
Author(s) -
BOONSTRA Johannes,
OTTEMA Sander,
SIPS Herman J.,
KONINGS Wil N.
Publication year - 1979
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1979.tb04253.x
Subject(s) - chemistry , vesicle , membrane , escherichia coli , ferricyanide , membrane potential , biochemistry , phospholipid , chemiosmosis , biophysics , enzyme , biology , atp synthase , gene
The barbiturate amytal (5‐ethyl‐5‐isopentylbarbituric acid) has been shown to inhibit amino acid transport in membrane vesicles from anaerobically grown Escherichia coli. Amytal has no effect on the activity of the enzymes of the nitrate respiration system, nor on electron transfer in this system. However, addition of amytal to the membrane vesicles results in a decrease of the membrane potential from −90 mV to −72 mV, and to a decrease of the pH‐gradient of ‐61 mV to undetectable values. Furthermore, amytal causes an increase in the rate of ferricyanide reduction in liposomes, indicating that amytal increases the proton permeability of phospholipid membranes. These results demonstrate that amytal acts as an uncoupler in membrane vesicles from anaerobically grown E. coli.