Preparation and properties of bacterial chromatophores entrapped in polyacrylamide

The immobilization of Rhodospirillum rubrum chromatophores was successfully performed by entrapping them in polyacrylamide. Their photophosphorylating activity was about 40% of native chromatophores. The temperature and pH optima for immobilized chromatophores were similar to the native photosynthetic apparatus and kinetic parameters showed that the rate of photophosphorylation in polyacrylamide particles was diffusion controlled. Light penetration of the gel particles was not a limiting parameter. Immobilization considerably increased the stability of the chromatophores towards denaturation.