Preparation and properties of chloroplasts depleted of chloroplast coupling factor 1 by sodium bromide treatment

Abstract

Chloroplasts were treated with 2 m sodium bromide. The resulting particles lost their ATPase activity and chloroplast coupling factor 1 subunits were detected in the supernatant by means of gel electrophoresis and specific antibodies. The chloroplast coupling factor 1 depleted particles show high rates of Hill reaction with pH optimum shifted toward lower pH. The sodium bromide treatment also abolished the light-induced proton uptake. In the presence of N-methylphenazonium methosulfate light-induced proton release, insensitive to uncouplers, was observed. Addition of dicyclohexylcarbodiimide reversed the light-induced pH changes to the normal proton uptake and increased the pH optimum of the Hill reaction.