Phosphofructokinase-1 (PFK-1) is a crucial regulatory enzyme in glycolysis that catalyzes the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate, effectively controlling the rate of glucose breakdown in cells. Its activity is allosterically regulated by various metabolites, including ATP, ADP, AMP, and citrate, allowing it to respond to the energy needs of the cell.