Uncoupling and charge transfer in bacterial chromatophores

Abstract

Uncoupling of photophosphorylation in bacterial chromatophores is obtained with NH 4Cl or K +(Na +) plus nigericin in the presence of either valinomycin or suitable permeant anions. The experiments suggest that uncoupling is obtained by the simultaneous abolishment of both pH gradient and membrane potential components of the light-induced electrochemical proton gradient, independently of the nature of the primary event in energy coupling. A general discussion of the relationship between uncoupling and the transfer of charge across the membranes of chromatophores, chloroplasts and submitochondrial particles is presented.