Catalytic subunit of pyrophosphate--fructose 6-phosphate 1-phosphotransferase. Catalyzes the phosphorylation of D-fructose 6-phosphate, the first committing step of glycolysis. Uses inorganic phosphate (PPi) as phosphoryl donor instead of ATP like common ATP-dependent phosphofructokinases (ATP-PFKs), which renders the reaction reversible, and can thus function both in glycolysis and gluconeogenesis. beta-D-fructose 6-phosphate + diphosphate = beta-D-fructose 1,6-bisphosphate + H(+) + phosphate Allosterically activated by fructose 2,6-bisphosphate. Carbohydrate degradation; glycolysis; D-glyceraldehyde 3-phosphate and glycerone phosphate from D-glucose: step 3/4. Tetramer of two alpha (regulatory) and two beta (catalytic) chains. Retarded growth and reduced pyrophosphate--fructose 6-phosphate 1-phosphotransferase (PFP) activity. Belongs to the phosphofructokinase type A (PFKA) family. PPi-dependent PFK group II subfamily. Clade 'Long' sub-subfamily.