Diphosphate concentration does not correlate with the level of inorganic diphosphatase in Escherichia coli

Partial inhibition of DNA synthesis stimulates the production of inorganic diphosphatase in Escherichia coli but the changes in diphosphate (PPi) level observed did not correlate with the enzyme activity. An accumulation of PPi was observed in the presence of inhibitors of RNA synthesis or nucleotide synthesis. In the former case the level of the enzyme did not change but in the latter case it increased. Thus the amount of inorganic diphosphatase alone does not determine the concentration of PPi in E. coli.