Phosphofructokinase(also known as 6-phosphofructokinase; PFK) is a class of kinases that act on fructose-6-phosphate. Phosphofructokinase catalyzes fructose-6-phosphate and ATP to produce fructose-1, 6-diphosphate and ADP, and pyruvate kinase and lactate dehydrogenase further catalyze the oxidation of NADH to NAD+. The activity of PFK can be reflected by the determination of NADH decline rate at 340 nm.