MetaCyc Pathway: galactitol degradation
Inferred from experiment

Pathway diagram: galactitol degradation

This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.

Synonyms: galactitol catabolism

Superclasses: Degradation/Utilization/AssimilationSecondary Metabolites DegradationSugar Derivatives DegradationSugar Alcohols Degradation

Some taxa known to possess this pathway include : Escherichia coli K-12 substr. MG1655

Expected Taxonomic Range: Proteobacteria

Of the ten existing hexitols ( allitol, D-altritol, L-altritol, D-sorbitol, L-sorbitol, D-mannitol, L-mannitol, D-Iditol, L-iditol and galactitol) only three occur naturally - D-mannitol, D-sorbitol (also known as D-glucitol), and galactitol (owing to symmetry, D- and L-galactitol are identical). Each of these can be utilized by bacteria as a total source of carbon and energy.

All three naturally-occurring hexitols can be utilized by bacteria as a total source of carbon and energy. Each of these hexitols enters the cell via a specific phosphotransferase system, so the first intracellular species is the 6-phospho-derivative [Lengeler75] (note that due to symmetry of D-mannitol and galactitol, their phosphorylation at either end produces the same molecule. When these molecules are phosphorylated at the 6 position by the PTS system, the resulting molecules are named D-mannitol 1-phosphate and galactitol 1-phosphate, respectively, by conventional nomenclature rules).

In all three cases this sugar alcohol phosphate becomes the substrate for a dehydrogenase that oxidizes its 2-alcohol group to a keto group. In the cases of D-mannitol and D-sorbitol, the resulting keto sugar phosphate is β-D-fructofuranose 6-phosphate, an intermediate of glycolysis, and hence it flows through the pathways of central metabolism to satisfy the cell's need for precursor metabolites, reducing power, and metabolic energy.

In the case of galactitol 1-phosphate, however, the product of the dehydrogenation is D-tagatofuranose 6-phosphate, which becomes the substrate of a kinase and subsequently an aldolase (in a pair of reactions that parallel those of glycolysis) before it is converted into intermediates ( D-glyceraldehyde 3-phosphate and glycerone phosphate) of glycolysis [Nobelmann96].

Superpathways: superpathway of hexitol degradation (bacteria)

Unification Links: EcoCyc:GALACTITOLCAT-PWY

Created 14-Oct-1996 by Riley M, Marine Biological Laboratory
Revised 09-May-2006 by Ingraham JL, UC Davis


Lengeler75: Lengeler J (1975). "Nature and properties of hexitol transport systems in Escherichia coli." J Bacteriol 124(1);39-47. PMID: 1100608

Nobelmann96: Nobelmann B, Lengeler JW (1996). "Molecular analysis of the gat genes from Escherichia coli and of their roles in galactitol transport and metabolism." J Bacteriol 1996;178(23);6790-5. PMID: 8955298

Other References Related to Enzymes, Genes, Subpathways, and Substrates of this Pathway

Atsumi10a: Atsumi S, Wu TY, Machado IM, Huang WC, Chen PY, Pellegrini M, Liao JC (2010). "Evolution, genomic analysis, and reconstruction of isobutanol tolerance in Escherichia coli." Mol Syst Biol 6;449. PMID: 21179021

Babul78: Babul J (1978). "Phosphofructokinases from Escherichia coli. Purification and characterization of the nonallosteric isozyme." J Biol Chem 1978;253(12);4350-5. PMID: 149128

Baez07: Baez M, Cabrera R, Guixe V, Babul J (2007). "Unfolding pathway of the dimeric and tetrameric forms of phosphofructokinase-2 from Escherichia coli." Biochemistry 46(20);6141-8. PMID: 17469854

Baez08: Baez M, Merino F, Astorga G, Babul J (2008). "Uncoupling the MgATP-induced inhibition and aggregation of Escherichia coli phosphofructokinase-2 by C-terminal mutations." FEBS Lett 582(13);1907-12. PMID: 18501195

Baez09: Baez M, Babul J (2009). "Reversible unfolding of dimeric phosphofructokinase-2 from Escherichia coli reveals a dominant role of inter-subunit contacts for stability." FEBS Lett 583(12);2054-60. PMID: 19465020

Baez11: Baez M, Wilson CA, Babul J (2011). "Folding kinetic pathway of phosphofructokinase-2 from Escherichia coli: a homodimeric enzyme with a complex domain organization." FEBS Lett 585(14);2158-64. PMID: 21627967

Baez12: Baez M, Wilson CA, Ramirez-Sarmiento CA, Guixe V, Babul J (2012). "Expanded monomeric intermediate upon cold and heat unfolding of phosphofructokinase-2 from Escherichia coli." Biophys J 103(10);2187-94. PMID: 23200052

Baez13: Baez M, Cabrera R, Pereira HM, Blanco A, Villalobos P, Ramirez-Sarmiento CA, Caniuguir A, Guixe V, Garratt RC, Babul J (2013). "A ribokinase family conserved monovalent cation binding site enhances the MgATP-induced inhibition in E. coli phosphofructokinase-2." Biophys J 105(1);185-93. PMID: 23823238

Benavente15: Benavente R, Esteban-Torres M, Kohring GW, Cortes-Cabrera A, Sanchez-Murcia PA, Gago F, Acebron I, de las Rivas B, Munoz R, Mancheno JM (2015). "Enantioselective oxidation of galactitol 1-phosphate by galactitol-1-phosphate 5-dehydrogenase from Escherichia coli." Acta Crystallogr D Biol Crystallogr 71(Pt 7);1540-54. PMID: 26143925

Bissett80: Bissett DL, Anderson RL (1980). "Lactose and D-galactose metabolism in Staphylococcus aureus. III. Purification and properties of D-tagatose-6-phosphate kinase." J Biol Chem 255(18);8745-9. PMID: 6251066

Bissett80a: Bissett DL, Anderson RL (1980). "Lactose and D-galactose metabolism in Staphylococcus aureus. IV. Isolation and properties of a class I D-ketohexose-1,6-diphosphate aldolase that catalyzes the cleavage of D-tagatose 1,6-diphosphate." J Biol Chem 255(18);8750-5. PMID: 7410392

Blankenhorn99: Blankenhorn D, Phillips J, Slonczewski JL (1999). "Acid- and base-induced proteins during aerobic and anaerobic growth of Escherichia coli revealed by two-dimensional gel electrophoresis." J Bacteriol 181(7);2209-16. PMID: 10094700

Bochkareva02: Bochkareva ES, Girshovich AS, Bibi E (2002). "Identification and characterization of the Escherichia coli stress protein UP12, a putative in vivo substrate of GroEL." Eur J Biochem 269(12);3032-40. PMID: 12071968

Brinkkotter00: Brinkkotter A, Kloss H, Alpert C, Lengeler JW (2000). "Pathways for the utilization of N-acetyl-galactosamine and galactosamine in Escherichia coli." Mol Microbiol 2000;37(1);125-35. PMID: 10931310

Brinkkotter02: Brinkkotter A, Shakeri-Garakani A, Lengeler JW (2002). "Two class II D-tagatose-bisphosphate aldolases from enteric bacteria." Arch Microbiol 177(5);410-9. PMID: 11976750

Cabrera02: Cabrera R, Guixe V, Alfaro J, Rodriguez PH, Babul J (2002). "Ligand-dependent structural changes and limited proteolysis of Escherichia coli phosphofructokinase-2." Arch Biochem Biophys 406(2);289-95. PMID: 12361717

Cabrera06: Cabrera R, Caniuguir A, Ambrosio AL, Guixe V, Garratt RC, Babul J (2006). "Crystallization and preliminary crystallographic analysis of the tetrameric form of phosphofructokinase-2 from Escherichia coli, a member of the ribokinase family." Acta Crystallogr Sect F Struct Biol Cryst Commun 62(Pt 9);935-7. PMID: 16946484

Cabrera08: Cabrera R, Ambrosio AL, Garratt RC, Guixe V, Babul J (2008). "Crystallographic structure of phosphofructokinase-2 from Escherichia coli in complex with two ATP molecules. Implications for substrate inhibition." J Mol Biol 383(3);588-602. PMID: 18762190

Cabrera10: Cabrera R, Babul J, Guixe V (2010). "Ribokinase family evolution and the role of conserved residues at the active site of the PfkB subfamily representative, Pfk-2 from Escherichia coli." Arch Biochem Biophys 502(1);23-30. PMID: 20599671

Cabrera11: Cabrera R, Baez M, Pereira HM, Caniuguir A, Garratt RC, Babul J (2011). "The crystal complex of phosphofructokinase-2 of Escherichia coli with fructose-6-phosphate: kinetic and structural analysis of the allosteric ATP inhibition." J Biol Chem 286(7);5774-83. PMID: 21147773

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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