[Effect of growth conditions on the activity of the enzymes of cyclic 3':5'-AMP synthesis and decay in phototrophic bacteria]

Abstract

Activity, ratio and summary content of cyclic AMP enzymes, adenylate cyclase and phosphodiesterase varied depending on growth conditions of phototrophic bacteria (Rhodospirillum rubrum and Rhodopseudomonas palustris). It suggests, that membrane-bound and soluble enzymes carry different functions. The increase of adenylate cyclase under chaning growth conditions was usually accompanied by the increase of phosphodiesterase. Sharp increase of both enzymes activity was observed when bacteria were growth in aerobic conditions. The activity of both enzymes in chromatophores was 2.8-fold higher when bacteria were grown in the light in anaerobic conditions, than in chromatophores of bacteria grown under stationary aerobic conditions in the light. It is suggested that 3':5' AMP can participate in autotrophic carbon assimilation or in the synthesis of pigments and other components of bacterial photosynthetizing apparatus. Substitution of NH4+ into NO3- and glutamate under the growing of R. rubrum in anaerobic conditions in the light resulted in the increase of the enzymes activities, which is the evidence of possible role of 3':5' AMP in mineral nitrogen uptake and nitrogen fixation. Glutamate concentration of 4 g/l stimulated the enzymes both in vivo and in vitro. The data obtained suggest that 3':5' AMP can carry multiple functions, participating in regulation of a number of metabolic processes in photorophic bacteria.