Respiration-dependent proton translocation and the mechanism of protonmotive force generation in Nitrobacter winogradskyi

Abstract

Proton translocation associated with electron flow to oxygen has been observed with cells of Nitrobacter winogradskyi in the presence of either potassium ferrocyanide or isoascorbate plus N,N,N′,N′ tetramethyl-p-phenylenediamine. The data are consistent with a proton pumping function for the terminal oxidase, cytochrome aa3, in this organism as the mechanism for generating a protonmotive force. The failure of previous work with Nitrobacter [4] to detect proton translocation linked to oxidation of nitrite, the physiological substrate, is discussed. © 1985.