Respiratory control in Micrococcus lysodeikticus.

The respiration rate of Pi-deprived cells of Micrococcus lysodeikticus is markedly increased by Pi, and returns to the original level following Pi consumption. The stimulation of the respiration was found to be specific for Pi and arsenate. Although succinate and valinomycin enhanced the respiration of both Pi-grown and Pi-deprived cells, only the latter could be further stimulated by Pi. The effect of Pi on the respiration rate was found to be concentration dependent. The control of respiration by Pi 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.