Expression of polyphosphate kinase inhibits the glucose uptake in Escherichia coli.

This paper examines the effects of phosphate pool and expression of polyphosphate kinase on glucose uptake by expressing the polyphosphate kinase under the control of lac promoter. The E. coli transformant of pL1, containing an IPTG controllable element for polyphosphate kinase expression, showed that the total intracellular phosphate significantly increased. However, the rate of glucose uptake by the resting plasmid-bearing cells with IPTG induction significantly decreased. These findings suggest that the polyphosphate can not directly function as an energy source in E. coli or at least not as a good energy supplier.