Absence of a unique relationship between active transport of lactose and protonmotive force in E. coli

The relationship between active transport of lactose via the lactose permease and the protonmotive force has been determined in E. coli cells using either the respiratory chain inhibitor cyanide or protonophores to decrease the protonmotive force progressively. In contradiction with the prediction of the delocalized chemiosmotic theory, two different relationships were obtained depending on the method used.