IUBMB Enzyme Nomenclature


Accepted name: protein-Nπ-phosphohistidine—N,N'-diacetylchitobiose phosphotransferase

Reaction: [protein]-Nπ-phospho-L-histidine + N,N'-diacetylchitobiose[side 1] = [protein]-L-histidine + N,N'-diacetylchitobiose 6'-phosphate[side 2]

Other name(s): chbABC (gene names); N,N'-diacetylchitobiose PTS permease; chitobiose PTS permease; EIIcel; EIIchb; Enzyme IIcel; Enzyme IIchb

Systematic name: protein-Nπ-phospho-L-histidine:N,N'-diacetylchitobiose 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 a phospho-carrier protein of low molecular mass that has been phosphorylated by EC (phosphoenolpyruvate—protein phosphotransferase). Enzyme II, on the other hand, is specific for a particular substrate, although in some cases alternative substrates can be transported with lower efficiency. 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. Keyhani, N.O., Wang, L.X., Lee, Y.C. and Roseman, S. The chitin disaccharide, N,N'-diacetylchitobiose, is catabolized by Escherichia coli and is transported/phosphorylated by the phosphoenolpyruvate:glycose phosphotransferase system. J. Biol. Chem. 275 (2000) 33084-33090. [PMID: 10913117]

2. Reizer, J., Reizer, A. and Saier, M.H., Jr. The cellobiose permease of Escherichia coli consists of three proteins and is homologous to the lactose permease of Staphylococcus aureus, Res. Microbiol. 141 (1990) 1061-1067. [PMID: 2092358]

3. Keyhani, N.O., Boudker, O. and Roseman, S. Isolation and characterization of IIAChb, a soluble protein of the enzyme II complex required for the transport/phosphorylation of N, N'-diacetylchitobiose in Escherichia coli, J. Biol. Chem. 275 (2000) 33091-33101. [PMID: 10913118]

4. Keyhani, N.O., Bacia, K. and Roseman, S. The transport/phosphorylation of N,N'-diacetylchitobiose in Escherichia coli. Characterization of phospho-IIB(Chb) and of a potential transition state analogue in the phosphotransfer reaction between the proteins IIA(Chb) AND IIB(Chb). J. Biol. Chem. 275 (2000) 33102-33109. [PMID: 10913119]

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

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