Regulation of glycogen synthesis and glucose utilization in Escherichia coli during maintenance of the energy charge. Quantitative correlation of changes in the rates of glycogen synthesis and glucose utilization with simultaneous changes in the cellular levels of both glucose 6-phosphate and fructose 1,6-diphosphate.

Treatment of nitrogen-starved cultures of Escherichia coli W4597(K) with sodium azide results in simultaneous changes in both glucose 6-phosphate and fructose 1,6-diphosphate as well as in the rate of glycogen synthesis. Based on these observations, a comprehensive equation was developed which relates the cellular levels of both of these hexose phosphates with the rate of glycogen synthesis. This relationship apparently represents the interaction in vivo between the rate-limiting enzyme of bacterial glycogen synthesis, glucose 1-phosphate adenylyltransferase (adenosine diphosphoglucose synthetase, EC 2.7.7.27), and its substrate glucose 1-phosphate (reflected by glucose 6-phosphate) and its major allosteric activator fructose diphosphate. The form of the equation that describes this relationship was determined from studies presented here of the kinetic properties of the E. coli W4597(K) enzyme in the presence of physiological concentrations of its substrates and modulators. We show here and in subsequent reports of this series that the comprehensive relationship between glycogen synthesis and hexose phosphates can serve as a reference to evaluate the possible participation of new factors in the regulation of glycogen synthesis. Treatment with NaN3 did not change the cellular level of glucose 1-phosphate adenylyltransferase. The value of the adenylate energy charge, (ATP + 1/2 ADP)/(ATP + ADP + AMP), was maintained despite losses of up to 35% in cellular adenylates. The quantitative co-variance between hexose phosphates and the cellular rate of glucose utilization that we previously described for other metabolic conditions was also observed in the azide-treated cultures. We integrate the new information into the system of coordinated regulation of glycogen synthesis, glycolysis, and glucose utilization that we proposed previously.