Purification and characterization of glpX-encoded fructose 1,6-bisphosphatase, a new enzyme of the glycerol 3-phosphate regulon of Escherichia coli

In Escherichia coli, gene products of the glp regulon mediate utilization o f glycerol and sn-glycerol 3-phosphate. The glpFKX operon encodes glycerol diffusion facilitator, glycerol kinase, and as shown here, a fructose 1,6-b isphosphatase that is distinct from the previously described fbp-encoded en zyme. The purified enzyme was dimeric, dependent on Mn2+ for activity, and exhibited an apparent K-m of 35 mu M for fructose 1,6-bisphosphate. The enz yme was inhibited by ADP and phosphate and activated by phosphoenolpyruvate .