The Kinetics of the Synthesis of Photopigments in Rhodopseudomonas spheroides

SUMMARY: The magnitude of self-shading in light-grown cultures of Rhodopseudomonas spheroides has been estimated. When a culture of R. spheroides is transferred from bright light to dim light there is preferential synthesis of bacteriochlorophyll and carotenoid pigments relative to net protein synthesis. Protein turnover does not account for this. The kinetics of the synthesis of bacteriochlorophyll relative to the incorporation of amino acids into protein have been estimated under a variety of conditions. On the basis of these findings a mechanism for the cellular control of pigment synthesis is presented.