Reaction: [protein]-Nπ-phospho-L-histidine + galactitol[side 1] = [protein]-L-histidine + galactitol 1-phosphate[side 2]
Other name(s): gatABC (gene names); galactitol PTS permease; EIIGat; Enzyme IIGat
Systematic name: protein-Nπ-phospho-L-histidine:galactitol 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 2.7.3.9 (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:
References:
1. Lengeler, J. Nature and properties of hexitol transport systems in Escherichia coli, J. Bacteriol. 124 (1975) 39-47. [PMID: 1100608]
2. Nobelmann, B. and Lengeler, J.W. Sequence of the gat operon for galactitol utilization from a wild-type strain EC3132 of Escherichia coli, Biochim. Biophys. Acta 1262 (1995) 69-72. [PMID: 7772602]
3. Nobelmann, B. and Lengeler, J.W. Molecular analysis of the gat genes from Escherichia coli and of their roles in galactitol transport and metabolism. J. Bacteriol. 178 (1996) 6790-6795. [PMID: 8955298]