PFKFB3, or 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3, is an enzyme that plays a key role in cellular energy metabolism, specifically glycolysis. It regulates the levels of fructose-2,6-bisphosphate (F2,6BP), a potent allosteric activator of 6-phosphofructo-1-kinase (PFK-1), a critical enzyme in glycolysis. By controlling F2,6BP levels, PFKFB3 promotes PFK-1 activity, enhancing the conversion of fructose-6-phosphate (F6P) to fructose-1,6-bisphosphate (F1,6BP) and increasing the flow of glucose through the glycolytic pathway.