IUBMB Enzyme Nomenclature


Accepted name: protein-Nπ-phosphohistidine—D-fructose phosphotransferase

Reaction: [protein]-Nπ-phospho-L-histidine + D-fructose[side 1] = [protein]-L-histidine + D-fructose 1-phosphate[side 2]

Other name(s): fruAB (gene names); fructose PTS permease; EIIFru; Enzyme IIFru

Systematic name: protein-Nπ-phospho-L-histidine:D-fructose Nπ-phosphotransferase

Comments: This enzyme is a component (known as enzyme II) of a phosphoenolpyruvate (PEP)-dependent, sugar transporting phosphotransferase system (PTS). The system, which is found only in prokaryotes, simultaneously transports its substrate from the periplasm or extracellular space into the cytoplasm and phosphorylates it. The phosphate donor, which is shared among the different systems, is usually a phospho-carrier protein of low molecular mass that has been phosphorylated by EC (phosphoenolpyruvate—protein phosphotransferase). The enzyme from the bacterium Escherichia coli is an exception, since it is phosphorylated directly by EC The reaction involves a successive transfer of the phosphate group to several amino acids within the enzyme before the final transfer to the substrate.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:


1. Waygood, E.B. Resolution of the phosphoenolpyruvate: fructose phosphotransferase system of Escherichia coli into two components: enzyme IIfructose and fructose-induced HPr-like protein (FPr). Can. J. Biochem. 58 (1980) 1144-1146. [PMID: 7006754]

2. Kornberg, H. The roles of HPr and FPr in the utilization of fructose by Escherichia coli, FEBS Lett. 194 (1986) 12-15. [PMID: 3510127]

3. Geerse, R.H., Izzo, F. and Postma, P.W. The PEP: fructose phosphotransferase system in Salmonella typhimurium: FPr combines enzyme IIIFru and pseudo-HPr activities. Mol. Gen. Genet. 216 (1989) 517-525. [PMID: 2546043]

4. Kornberg, H.L. and Lambourne, L.T. Role of the phosphoenolpyruvate-dependent fructose phosphotransferase system in the utilization of mannose by Escherichia coli, Proc Biol Sci 250 (1992) 51-55. [PMID: 1361062]

[EC created 1972 as EC, part transferred 2016 to EC]

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