Cytosolic phosphofructokinase 2 (PFK2) catalyzes the irreversible reaction of fructose 6-phosphate and ATP to form fructose 2,6-bisphosphate and ADP. Fructose 2,6-bisphosphate is not an intermediate in the pathway from glucose 6-phosphate to pyruvate, but rather is a strong allosteric activator of the enzyme (PFK1) that catalyzes the synthesis of fructose 1,6-bisphosphate, and in mammalian systems regulation of fructose 2,6-bisphosphate levels plays a central role in regulating the rate of glycolysis. The chicken enzyme has been purified and shown to form a catalytically active dimer, though its role in the overall regulation of glycolysis is not fully worked out (Li et al. 1993; Van Schaftingen and Hers 1986). Two additional proteins, PFK2-like1 and 2, are predicted to have phosphofructokinase 2 activity based on OrthoMCL analysis of the ENSEMBL chicken gene set. Both of these are annotated here as monomers as no data concerning their biochemical properties are available.