Phosphofructokinase, a key regulatory enzyme in glycolysis, catalyzes the phosphorylation of fructose-6-phosphate to fructose-1,6-biphosphate. The members belong to a subfamily of the PFKA family (cd00363) and include pyrophosphate-dependent phosphofructokinases. These are found in bacteria as well as plants. These may be dimeric nonallosteric enzymes as in bacteria or allosteric heterotetramers as in plants.