Purification and Characterization of glpX -Encoded Fructose 1,6-Bisphosphatase, a New Enzyme of the Glycerol 3-Phosphate Regulon of Escherichia coli

Abstract

In Escherichia coli, gene products of theglp regulon mediate utilization of glycerol andsn-glycerol 3-phosphate. The glpFKX operon encodes glycerol diffusion facilitator, glycerol kinase, and as shown here, a fructose 1,6-bisphosphatase that is distinct from the previously described fbp-encoded enzyme. The purified enzyme was dimeric, dependent on Mn²⁺ for activity, and exhibited an apparent K_m of 35 μM for fructose 1,6-bisphosphate. The enzyme was inhibited by ADP and phosphate and activated by phosphoenolpyruvate.