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MetaCyc Pathway: toluene degradation to 2-oxopent-4-enoate (via toluene-cis-diol)
Inferred from experiment

Pathway diagram: toluene degradation to 2-oxopent-4-enoate (via toluene-cis-diol)

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: toluene degradation via toluene-cis-diol

Superclasses: Degradation/Utilization/AssimilationAromatic Compounds DegradationToluenes Degradation

Some taxa known to possess this pathway include : Pseudomonas putida F1

Expected Taxonomic Range: Proteobacteria

Toluene is widely used as an industrial additive and solvent. Toluene and related aromatic compounds can be degraded by bacteria, and have been studied in the metabolically versatile genus Pseudomonas and closely related genera. These studies have been directed toward bioremediation of environmental pollutants by metabolic engineering, and the development of syntrophic bacterial consortia (reviewed in [Diaz04]). Aerobic pathways of toluene degradation have been identified in various species that involve different initial monooxygenase, or hydroxylating dioxygenase reactions. Several of these pathways converge in the formation of 2,3-dihydroxytoluene (3-methylcatechol) [Shields91]. This compound is a substrate for ring cleavage enzymes, the products of which are metabolized via a common meta fission pathway, resulting in the formation of compounds of central metabolism (see this pathway and MetaCyc pathways toluene degradation to 2-oxopent-4-enoate (via 4-methylcatechol) and toluene degradation to 2-oxopent-4-enoate I (via o-cresol)).

The chromosome of Pseudomonas putida F1 contains a gene cluster encoding enzymes that allow this organism to grow on toluene and related compounds as sole carbon and energy source [Zylstra89, Menn91, Lau94]. Other strains of P. putida may contain plasmid-encoded genes for toluene degradation (see MetaCyc pathway toluene degradation to benzoate). The inducible toluene dioxygenase enzyme hydroxylates toluene to its dihydrodiol derivative by incorporating both atoms of an oxygen molecule into the aromatic nucleus. The dihydroxylated derivative is dehydrogenated to a catechol. Ring fission of the catechol 2,3-dihydroxytoluene (3-methylcatechol) is catalyzed by catechol 2,3-dioxygenase to produce cis,cis-2-hydroxy-6-oxohepta-2,4-dienoate. This compound is hydrolyzed to 2-oxopent-4-enoate, or its tautomeric dienol form cis-2-hydroxypenta-2,4-dienoate. This tautomerization occurs spontaneously in aqueous solution [Johnson04a]. It is not known which tautomeric form is produced by the hydrolase, and which form is used by the hydratase of P. putida F1 in this pathway. However, it has been suggested that the Pseudomonas putida mt-2 hydratase, encoded by the TOL plasmid pWW0, uses the dienol form as a substrate [Harayama89], and there is evidence that the Escherichia coli hydratase also uses the dienol form as substrate, producing a ketonized intermediate in the reaction mechanism [Pollard98]. The products of the pathway are pyruvate, which enters central metabolism, and acetaldehyde, which may be converted by acylating aldehyde dehydrogenase to acetyl-CoA, a central metabolite [Lau94].

Superpathways: superpathway of aromatic compound degradation via 2-oxopent-4-enoate, toluene degradation V (aerobic) (via toluene-cis-diol), superpathway of aerobic toluene degradation

Variants: 2,4-xylenol degradation to protocatechuate, 4-methylphenol degradation to protocatechuate, toluene degradation I (aerobic) (via o-cresol), toluene degradation II (aerobic) (via 4-methylcatechol), toluene degradation III (aerobic) (via p-cresol), toluene degradation IV (aerobic) (via catechol), toluene degradation to 2-oxopent-4-enoate (via 4-methylcatechol), toluene degradation to 2-oxopent-4-enoate I (via o-cresol), toluene degradation to 4-methylphenol, toluene degradation to benzoate, toluene degradation to benzoyl-CoA (anaerobic), toluene degradation VI (anaerobic)

Relationship Links: Eawag-BBD-Pathways:RELATED-TO:tol

Created 26-Oct-1998 by Krieger CJ, SRI International
Revised 21-Sep-2005 by Fulcher CA, SRI International
Revised 12-May-2006 by Caspi R, SRI International


Diaz04: Diaz E (2004). "Bacterial degradation of aromatic pollutants: a paradigm of metabolic versatility." Int Microbiol 7(3);173-80. PMID: 15492931

Harayama89: Harayama S, Rekik M, Ngai KL, Ornston LN (1989). "Physically associated enzymes produce and metabolize 2-hydroxy-2,4-dienoate, a chemically unstable intermediate formed in catechol metabolism via meta cleavage in Pseudomonas putida." J Bacteriol 171(11);6251-8. PMID: 2681159

Johnson04a: Johnson WH, Wang SC, Stanley TM, Czerwinski RM, Almrud JJ, Poelarends GJ, Murzin AG, Whitman CP (2004). "4-Oxalocrotonate tautomerase, its homologue YwhB, and active vinylpyruvate hydratase: synthesis and evaluation of 2-fluoro substrate analogues." Biochemistry 43(32);10490-501. PMID: 15301547

Lau94: Lau PC, Bergeron H, Labbe D, Wang Y, Brousseau R, Gibson DT (1994). "Sequence and expression of the todGIH genes involved in the last three steps of toluene degradation by Pseudomonas putida F1." Gene 1994;146(1);7-13. PMID: 8063106

Menn91: Menn FM, Zylstra GJ, Gibson DT (1991). "Location and sequence of the todF gene encoding 2-hydroxy-6-oxohepta-2,4-dienoate hydrolase in Pseudomonas putida F1." Gene 1991;104(1);91-4. PMID: 1916282

Pollard98: Pollard JR, Bugg TD (1998). "Purification, characterisation and reaction mechanism of monofunctional 2-hydroxypentadienoic acid hydratase from Escherichia coli." Eur J Biochem 251(1-2);98-106. PMID: 9492273

Shields91: Shields MS, Montgomery SO, Cuskey SM, Chapman PJ, Pritchard PH (1991). "Mutants of Pseudomonas cepacia G4 defective in catabolism of aromatic compounds and trichloroethylene." Appl Environ Microbiol 57(7);1935-41. PMID: 1892384

Zylstra89: Zylstra GJ, Gibson DT (1989). "Toluene degradation by Pseudomonas putida F1. Nucleotide sequence of the todC1C2BADE genes and their expression in Escherichia coli." J Biol Chem 264(25);14940-6. PMID: 2670929

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

Bagneris05: Bagneris C, Cammack R, Mason JR (2005). "Subtle difference between benzene and toluene dioxygenases of Pseudomonas putida." Appl Environ Microbiol 71(3);1570-80. PMID: 15746362

Furukawa93: Furukawa K, Hirose J, Suyama A, Zaiki T, Hayashida S (1993). "Gene components responsible for discrete substrate specificity in the metabolism of biphenyl (bph operon) and toluene (tod operon)." J Bacteriol 175(16);5224-32. PMID: 8349562

Haigler94: Haigler BE, Wallace WH, Spain JC (1994). "Biodegradation of 2-nitrotoluene by Pseudomonas sp. strain JS42." Appl Environ Microbiol 60(9);3466-9. PMID: 7944378

He99: He Z, Spain JC (1999). "Comparison of the downstream pathways for degradation of nitrobenzene by Pseudomonas pseudoalcaligenes JS45 (2-aminophenol pathway) and by Comamonas sp. JS765 (catechol pathway)." Arch Microbiol 171(5);309-16. PMID: 10382261

Hugo00: Hugo N, Meyer C, Armengaud J, Gaillard J, Timmis KN, Jouanneau Y (2000). "Characterization of three XylT-like [2Fe-2S] ferredoxins associated with catabolism of cresols or naphthalene: evidence for their involvement in catechol dioxygenase reactivation." J Bacteriol 182(19);5580-5. PMID: 10986264

Jiang96b: Jiang H, Parales RE, Lynch NA, Gibson DT (1996). "Site-directed mutagenesis of conserved amino acids in the alpha subunit of toluene dioxygenase: potential mononuclear non-heme iron coordination sites." J Bacteriol 178(11);3133-9. PMID: 8655491

Jiang99a: Jiang H, Parales RE, Gibson DT (1999). "The alpha subunit of toluene dioxygenase from Pseudomonas putida F1 can accept electrons from reduced FerredoxinTOL but is catalytically inactive in the absence of the beta subunit." Appl Environ Microbiol 65(1);315-8. PMID: 9872799

Kukor91: Kukor JJ, Olsen RH (1991). "Genetic organization and regulation of a meta cleavage pathway for catechols produced from catabolism of toluene, benzene, phenol, and cresols by Pseudomonas pickettii PKO1." J Bacteriol 1991;173(15);4587-94. PMID: 1856161

Kukor96: Kukor JJ, Olsen RH (1996). "Catechol 2,3-dioxygenases functional in oxygen-limited (hypoxic) environments." Appl Environ Microbiol 62(5);1728-40. PMID: 8633871

Lange97: Lange CC, Wackett LP (1997). "Oxidation of aliphatic olefins by toluene dioxygenase: enzyme rates and product identification." J Bacteriol 179(12);3858-65. PMID: 9190800

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Li92c: Li S, Wackett LP (1992). "Trichloroethylene oxidation by toluene dioxygenase." Biochem Biophys Res Commun 185(1);443-51. PMID: 1599483

Okuta04: Okuta A, Ohnishi K, Harayama S (2004). "Construction of chimeric catechol 2,3-dioxygenase exhibiting improved activity against the suicide inhibitor 4-methylcatechol." Appl Environ Microbiol 70(3);1804-10. PMID: 15006807

Robertson92: Robertson JB, Spain JC, Haddock JD, Gibson DT (1992). "Oxidation of nitrotoluenes by toluene dioxygenase: evidence for a monooxygenase reaction." Appl Environ Microbiol 58(8);2643-8. PMID: 1514810

Rogers77: Rogers JE, Gibson DT (1977). "Purification and properties of cis-toluene dihydrodiol dehydrogenase from Pseudomonas putida." J Bacteriol 130(3);1117-24. PMID: 16865

Shields95: Shields MS, Reagin MJ, Gerger RR, Campbell R, Somerville C (1995). "TOM, a new aromatic degradative plasmid from Burkholderia (Pseudomonas) cepacia G4." Appl Environ Microbiol 1995;61(4);1352-6. PMID: 7538275

Subramanian81: Subramanian V, Liu TN, Yeh WK, Narro M, Gibson DT (1981). "Purification and properties of NADH-ferredoxinTOL reductase. A component of toluene dioxygenase from Pseudomonas putida." J Biol Chem 256(6);2723-30. PMID: 7204373

Subramanian85: Subramanian V, Liu TN, Yeh WK, Serdar CM, Wackett LP, Gibson DT (1985). "Purification and properties of ferredoxinTOL. A component of toluene dioxygenase from Pseudomonas putida F1." J Biol Chem 260(4);2355-63. PMID: 2982815

Wackett90: Wackett LP (1990). "Toluene dioxygenase from Pseudomonas putida F1." Methods Enzymol 188;39-45. PMID: 2280710

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by Pathway Tools version 19.5 (software by SRI International) on Fri Apr 29, 2016, biocyc11.