6-Phosphofructo-2-Kinase/Fructose-2,6-Biphosphatase 4 (PFKFB4)

The bifunctional PFKFB regulates the steady-state concentration of fructose-2,6-bisphosphate, a potent activator of a key regulatory enzyme of glycolysis, phosphofructokinase. Isozymes of PFKFB differ in the regions surrounding the catalytic core, which are important for the differential response to allosteric effectors and hormonal signals in different tissues.The predicted 469-amino acid PFKFB4 protein, which is 97% homologous to the rat sequence and approximately 70% identical to the human PFKFB isoforms, contains multiple phosphorylation sites. Northern blot analysis of rat brain, heart, liver, muscle, placenta, adipose tissue, ovary, fallopian tubes, and testis with the human PFKFB4 sequence as probe detected testis-specific expression of 2.4- and 3.3-kb transcripts.