Respiratory control in Micrococcus lysodeikticus

The respiration rate of P_i-deprived cells of Micrococcus lysodeikticus is markedly increased by P_i, and returns to the original level following P_i consumption. The stimulation of the respiration was found to be specific for P_i and arsenate. Although succinate and valinomycin enchanced the respiration of both P_i-grown and P_i-deprived cells, only the latter could be further stimulated by P_i. The effect of P_i on the respiration rate was found to be concentration dependent. The control of respiration by P_i is due to its rapid uptake and its subsequent polymerization to polyphosphate via ATP. Both of these processes are coupled to proton influx into the cell, and thus stimulate the proton efflux and the respiration rate.