Relationship of a Proton Gradient to the Active Transport of Proline with Membrane Vesicles from Mycobacterium phlei

Electron transport particles prepared from Mycobacterium phlei were depleted of bound coupling factors by washing with water in the absence of inorganic ions. The depleted electron transport particles were void of latent ATPase activity and were capable of oxidation, but were unable to support coupled phosphorylation. Nevertheless, the depleted electron transport particles were capable of substrate-induced active transport of proline. Changes in pH in response to substrate oxidation were measured in normal and depleted electron particles with bromthymol blue. A bromthymol blue response upon substrate oxidation was not observed with depleted electron transport particles. The level of oxidative phosphorylation with succinate or NADH oxidation was not reduced in the presence of proline, and proline did not have an effect upon the proton gradients formed by the oxidation of either succinate or NADH.