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/Assimilation → Secondary Metabolites Degradation → Sugar Derivatives Degradation → Sugar 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 dihydroxyacetone phosphate) of glycolysis [Nobelmann96].
Superpathways: superpathway of hexitol degradation (bacteria)
Unification Links: EcoCyc:GALACTITOLCAT-PWY
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
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
Baez13a: 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
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
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
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
Caniuguir05: Caniuguir A, Cabrera R, Baez M, Vasquez CC, Babul J, Guixe V (2005). "Role of Cys-295 on subunit interactions and allosteric regulation of phosphofructokinase-2 from Escherichia coli." FEBS Lett 579(11);2313-8. PMID: 15848164
Daldal83: Daldal F (1983). "Molecular cloning of the gene for phosphofructokinase-2 of Escherichia coli and the nature of a mutation, pfkB1, causing a high level of the enzyme." J Mol Biol 1983;168(2);285-305. PMID: 6310120
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