pts-gfl superfamily pts-gfl superfamily the phosphotransferases system (pts-gfl) superfamily is a superfamily of phosphotransferase enzymes that facilitate the transport of glucose, glucitol (g), fructose (f) and lactose (l). classification has been established through phylogenic analysis and bioinformatics. the bacterial phosphoenolpyruvate:sugar phosphotransferase system (pts) transports and phosphorylates its sugar substrates in a single energy-coupled step. this transport process is dependent on several cytoplasmic phosphoryl transfer proteins - enzyme i (i), hpr, enzyme iia (iia), and enzyme iib (iib)) as well as the integral membrane sugar permease (iic). the pts enzyme ii complexes are derived from independently evolving 4 pts enzyme ii complex superfamilies, that include the (1) glucose (glc),(2) mannose (man), (3) ascorbate-galactitol (asc-gat) and (4) dihydroxyacetone (dha) superfamilies. the four families that make up the pts-gfl superfamily include: 4.a.1 – the pts glucose-glucoside (glc) family 4.a.2 – the pts fructose-mannitol (fru) family 4.a.3 – the pts lactose-n,n'-diacetylchitobiose-β-glucoside (lac) family 4.a.4 – the pts glucitol (gut) family