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.
|Superclasses:||Degradation/Utilization/Assimilation → Inorganic Nutrients Metabolism → Nitrogen Compounds Metabolism → Taurine Degradation|
|Degradation/Utilization/Assimilation → Inorganic Nutrients Metabolism → Sulfur Compounds Metabolism → Taurine Degradation|
Some taxa known to possess parts of the pathway include : Achromobacter superficialis , Bilophila wadsworthia RZATAU , Desulfonispora thiosulfatigenes GKNTAU , Escherichia coli K-12 substr. MG1655 , Paracoccus denitrificans NKNIS , Rhodococcus opacus
Expected Taxonomic Range:
Note: This is a chimeric pathway, comprising reactions from multiple organisms, and typically will not occur in its entirety in a single organism. The taxa listed here are likely to catalyze only subsets of the reactions depicted in this pathway.
Please note: This pathway does not represent a single organism. Rather, it is a super-pathway assembled from many pathways found in a variety of organisms, whose purpose is to provide an overview of the metabolic capabilities of the ecosystem, pertaining to degradation of taurine.
Taurine (2-aminoethanesulfonate), a natural occuring amino acid analogue of β-alanine, plays several important roles in mammals and is essential to newborns of many species. The main functions of taurine in mammals include bile acid conjugation, detoxification, osmoregulation, membrane stabilization, and regulation of intracellular Ca2+ homeostasis. While plants or animals cannot degrade taurine, several species of bacteria and fungi are capable of doing that. For example, Pseudomonas aeruginosa TAU-5 can grow on taurine as the sole source of carbon, nitrogen, sulfur and energy [Shimamoto79].
Some anaerobic bacteria can use taurine for respiration as either an electron acceptor (eg. Bilophila wadsworthia RZATAU) or an electron donor (eg. Castellaniella defragrans NKNTAU, Paracoccus denitrificans NKNIS, and Paracoccus pantotrophus NKNCYSA). Others can use it as a fermentative substrate (eg. Desulfonispora thiosulfatigenes GKNTAU) [Cook02, Denger97].
The different species often utilize different pathways, resulting in conversion of taurine into different sulfur compounds. For example: Bilophila wadsworthia RZATAU converts taurine to sulfoacetaldehyde [Laue00], which is cleaved to sulfite [Laue01], and eventually converted to sulfide by a sulfite reductase [Laue97]. A. defragrans NKNTAU [Denger97a], Paracoccus denitrificans NKNIS (as reported in [Cook02]), and P. pantotrophus NKNCYSA (as reported in [Cook02]), all convert taurine to sulfate (additional products are ammonia and CO2), while Desulfonispora thiosulfatigenes GKNTAU converts taurine to thiosulfate, ammonia and acetate [Denger97].
Taurine degradation is known to be initiated by at least three different types of reactions: transamination, which appears to be the most widespread [Shimamoto79, Toyama72, Toyama72a, Toyama78], oxidation [Kondo71], and oxygenation [Eichhorn97]. In the first two cases sulfoacetaldehyde is an intermediate, whereas in the third case taurine is converted to sulfite and aminoacetaldehyde [Eichhorn97].
Two aminotransferases involved in taurine dissimilation have been described, taurine:pyruvate aminotransferase in Pseudomonas aeruginosa TAU-5 and Bilophila wadsworthia RZATAU [Shimamoto79, Laue00] and taurine:α-ketoglutarate aminotransferase in Achromobacter superficialis [Toyama72, Toyama72a, Toyama78]. Cook and Denger [Cook02] speculated that the physiological role of taurine:α-ketoglutarate aminotransferase in Achromobacter superficialis is for transamination of β-alanine and not taurine, since the enzyme is induced by β-alanine and not taurine.
Taurine:pyruvate aminotransferase transfers the amino group from taurine to L-alanine. Alanine dehydrogenase (EC 18.104.22.168) catalyzes the oxidative deamination of alanine to pyruvate, regenerating the amino-group acceptor pyruvate, and releasing ammonium. Alanine dehydrogenase from Bilophila wadsworthia RZATAU was purified and characterized [Laue00a].
Eichhorn97: Eichhorn E, van der Ploeg JR, Kertesz MA, Leisinger T (1997). "Characterization of alpha-ketoglutarate-dependent taurine dioxygenase from Escherichia coli." J Biol Chem 1997;272(37);23031-6. PMID: 9287300
Laue00a: Laue H, Cook AM (2000). "Purification, properties and primary structure of alanine dehydrogenase involved in taurine metabolism in the anaerobe Bilophila wadsworthia." Arch Microbiol 174(3);162-7. PMID: 11041346
Laue01: Laue H, Friedrich M, Ruff J, Cook AM (2001). "Dissimilatory sulfite reductase (desulfoviridin) of the taurine-degrading, non-sulfate-reducing bacterium Bilophila wadsworthia RZATAU contains a fused DsrB-DsrD subunit." J Bacteriol 183(5);1727-33. PMID: 11160104
Toyama78: Toyama S, Misono H, Soda K (1978). "Properties of taurine: alpha-ketoglutarate aminotransferase of Achromobacter superficialis. Inactivation and reactivation of enzyme." Biochim Biophys Acta 523(1);75-81. PMID: 629994
Atteia06: Atteia A, van Lis R, Gelius-Dietrich G, Adrait A, Garin J, Joyard J, Rolland N, Martin W (2006). "Pyruvate formate-lyase and a novel route of eukaryotic ATP synthesis in Chlamydomonas mitochondria." J Biol Chem 281(15);9909-18. PMID: 16452484
Avison01: Avison MB, Horton RE, Walsh TR, Bennett PM (2001). "Escherichia coli CreBC is a global regulator of gene expression that responds to growth in minimal media." J Biol Chem 276(29);26955-61. PMID: 11350954
Bergmeyer63: Bergmeyer, H.U., Holz, G., Klotzsch, H., Lang, G. (1963). "[Phosphotransacetylase from Clostridium kluyveri. Culture of the bacterium, isolation, crystallization and properties of the enzyme.]." Biochem Z 338;114-21. PMID: 14087284
Bock99: Bock AK, Glasemacher J, Schmidt R, Schonheit P (1999). "Purification and characterization of two extremely thermostable enzymes, phosphate acetyltransferase and acetate kinase, from the hyperthermophilic eubacterium Thermotoga maritima." J Bacteriol 1999;181(6);1861-7. PMID: 10074080
Bologna10: Bologna FP, Campos-Bermudez VA, Saavedra DD, Andreo CS, Drincovich MF (2010). "Characterization of Escherichia coli EutD: a phosphotransacetylase of the ethanolamine operon." J Microbiol 48(5);629-36. PMID: 21046341
Butland05: Butland G, Peregrin-Alvarez JM, Li J, Yang W, Yang X, Canadien V, Starostine A, Richards D, Beattie B, Krogan N, Davey M, Parkinson J, Greenblatt J, Emili A (2005). "Interaction network containing conserved and essential protein complexes in Escherichia coli." Nature 433(7025);531-7. PMID: 15690043
CamposBermudez10: Campos-Bermudez VA, Bologna FP, Andreo CS, Drincovich MF (2010). "Functional dissection of Escherichia coli phosphotransacetylase structural domains and analysis of key compounds involved in activity regulation." FEBS J 277(8);1957-66. PMID: 20236319
CastanoCerezo09: Castano-Cerezo S, Pastor JM, Renilla S, Bernal V, Iborra JL, Canovas M (2009). "An insight into the role of phosphotransacetylase (pta) and the acetate/acetyl-CoA node in Escherichia coli." Microb Cell Fact 8;54. PMID: 19852855
Chae11: Chae, Lee (2011). "The functional annotation of protein sequences was performed by the in-house Ensemble Enzyme Prediction Pipeline (E2P2, version 1.0). E2P2 systematically integrates results from three molecular function annotation algorithms using an ensemble classification scheme. For a given genome, all protein sequences are submitted as individual queries against the base-level annotation methods. The individual methods rely on homology transfer to annotate protein sequences, using single sequence (BLAST, E-value cutoff <= 1e-30, subset of SwissProt 15.3) and multiple sequence (Priam, November 2010; CatFam, version 2.0, 1% FDR profile library) models of enzymatic functions. The base-level predictions are then integrated into a final set of annotations using an average weighted integration algorithm, where the weight of each prediction from each individual method was determined via a 0.632 bootstrap process over 1000 rounds of testing. The training and testing data for E2P2 and the BLAST reference database were drawn from protein sequences with experimental support of existence, compiled from SwissProt release 15.3."
Chang99: Chang DE, Shin S, Rhee JS, Pan JG (1999). "Acetate metabolism in a pta mutant of Escherichia coli W3110: importance of maintaining acetyl coenzyme A flux for growth and survival." J Bacteriol 181(21);6656-63. PMID: 10542166
De07a: De Mey M, Lequeux GJ, Beauprez JJ, Maertens J, Van Horen E, Soetaert WK, Vanrolleghem PA, Vandamme EJ "Comparison of different strategies to reduce acetate formation in Escherichia coli." Biotechnol Prog 23(5);1053-63. PMID: 17715942
Denger01: Denger K, Ruff J, Rein U, Cook AM (2001). "Sulphoacetaldehyde sulpho-lyase (EC 22.214.171.124) from Desulfonispora thiosulfatigenes: purification, properties and primary sequence." Biochem J 357(Pt 2);581-6. PMID: 11439112
Denger04: Denger K, Ruff J, Schleheck D, Cook AM (2004). "Rhodococcus opacus expresses the xsc gene to utilize taurine as a carbon source or as a nitrogen source but not as a sulfur source." Microbiology 150(Pt 6);1859-67. PMID: 15184572
Denger09: Denger K, Mayer J, Buhmann M, Weinitschke S, Smits TH, Cook AM (2009). "Bifurcated degradative pathway of 3-sulfolactate in Roseovarius nubinhibens ISM via sulfoacetaldehyde acetyltransferase and (S)-cysteate sulfolyase." J Bacteriol 191(18);5648-56. PMID: 19581363
DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114
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