[Electrochemical potential difference for H+-ions as a regulator of redox profile of membrane during ATP-dependent ion transport in E. coli].

The importance of delta mu H+ for transport of K+ via K(+)-ionophore and H(+)-K(+)-pump was studied. It was shown that the operation of the pump was decelerated by oxidant ferrycyanide, whereas sulfhydryl reagent dithiothreitol (DTT) drastically accelerated ATP driven ion exchange. Introduction of protonophore CCCP into the medium completely blocked the pump operation. However, the addition of DTT after CCCP restored the high level activity of the pump. At the same time DTT was unable to restore K+ accumulation after CCCP in aerobically grown bacteria for which the K+ uptake was performed across the electrical field gradient. Thus it was established that delta mu H+ was necessary for ATP driven ionic systems as a regulator of the membrane redox state.