The protein encoded by this gene is involved in both the synthesis and degradation of fructose-2,6-bisphosphate, a regulatory molecule that controls glycolysis in eukaryotes. The encoded protein has a 6-phosphofructo-2-kinase activity that catalyzes the synthesis of fructose-2,6-bisphosphate, and a fructose-2,6-biphosphatase activity that catalyzes the degradation of fructose-2,6-bisphosphate. This protein regulates fructose-2,6-bisphosphate levels in the heart, while a related enzyme encoded by a different gene regulates fructose-2,6-bisphosphate levels in the liver and muscle. This enzyme functions as a homodimer. Two transcript variants encoding two different isoforms have been found for this gene. [provided by RefSeq, Jul 2008],catalytic activity:ATP + D-fructose 6-phosphate = ADP + beta-D-fructose 2,6-bisphosphate.,catalytic activity:Beta-D-fructose 2,6-bisphosphate + H(2)O = D-fructose 6-phosphate + phosphate.,enzyme regulation:Phosphorylation results in the activation of the kinase activity.,function:Synthesis and degradation of fructose 2,6-bisphosphate.,similarity:In the C-terminal section; belongs to the phosphoglycerate mutase family.,subunit:Homodimer.,tissue specificity:Heart.,