The inhibition of photosynthetic electron transfer in Rhodospirillum rubrum by N ,N' -dicyclohexylcarbodiimide

N ,N' -Dicyclohexylcarbodiimide (DCCD) at concentrations above 0.1 mM inhibits light-induced generation of a membrane potential in the course of cyclic and non-cyclic electron transfer, as well as light-induced oxygen uptake due to interaction of photoreduced secondary (loosely bound) ubiquinone with O2 in Rhodospirillum rubrum chromatophores. Similarly to o-phenanthroline, DCCD blocks the electron transfer in the chromatophores between the primary (tightly bound) and secondary ubiquinones.