Fructose 2,6-bisphosphatase

Fructose-2,6-bisphosphatase is an enzyme that catalyzes the following reaction:

fructose-2,6-bisphosphate + H2O ---> fructose-6-phosphate + phosphate ion

Fructose-2,6-bisphosphatase is important in regulation of gluconeogenesis & glycolysis as it catalyzes the dephosphorylation of fructose-2,6-bisphosphate. Because fructose-2,6-bisphosphate activates phosphofructokinase-1 (a critical enzyme in glycolysis) and inhibits fructose-1,6-bisphosphatase (a critical enzyme in gluconeogenesis), the activity of fructose-2,6-bisphosphatase decreases glycolysis and increases gluconeogenesis.

Fructose-2,6-bisphosphatase is subject to product inhibition by fructose-6-phosphate. Fructose-2,6-bisphosphatase also undergoes addition of a phosphate group to a single serine residue by cAMP-dependent protein kinase (known as covalent modification), which activates (increases catalytic activity) of Fructose-2,6-bisphosphatase.