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 → Aromatic Compounds Degradation → Gallate Degradation|
Expected Taxonomic Range: Bacteria
Gallate and structurally related compounds are widely distributed in nature. Plant lignin and tannins are major sources of these compounds, which are degraded by soil microorganisms as part of the terrestrial carbon cycle. Gallate is also used industrially in inks and paints, and gallate esters are used as food, cosmetics and pharmaceutical antioxidants. Gallate and its derivatives are also of interest in drug development (reviewed in [Ow03].
Gallate and related compounds contain a benzene nucleus and at least 2 phenolic hydroxyl groups. Under aerobic conditions the benzene ring is cleaved by varioius dioxygenases. The benzene nucleus can be cleaved by ortho or meta fission enzymes, leading to different degradation pathways. Several distinct pathways of aerobic aromatic catabolism can be initiated by these dioxygenases, and their distribution among bacteria is complex [Gottschalk86]. Examples of these oxidative pathways are shown in MetaCyc pathways gallate degradation II, methylgallate degradation, protocatechuate degradation I (meta-cleavage pathway), protocatechuate degradation II (ortho-cleavage pathway), and superpathway of aromatic compound degradation via 3-oxoadipate. An anaerobic pathway for gallate degradation is shown in MetaCyc pathway gallate degradation III (anaerobic).
About This Pathway
Fluorescent pseudomonads such as Pseudomonas putida can cleave gallate using the inducible ortho fission enzyme, protocatechuate 3,4-dioxygenase. However, the product 2-pyrone-4,6-dicarboxylate (PDC) is usually not degraded further due to the lack of an enzyme that can process PDC. A strain that contains a 2-pyrone-4,6-dicarboxylate hydrolase enzyme was isolated from soil by selection for growth on PDC as the sole carbon source, and named Pseudomonas putida PDC. Extracts of cells grown with PDC contained the hydrolase and high levels of gallate dioxygenase, but demonstrated only low activity against protocatechuate. Cells adapted to gallate expressed the hydrolase while cells adapted to protocatechuate did not. Thin layer chromatography of derivatized catabolites produced by cells grown with PDC revealed 4-carboxy-2-oxo-3-hexenedioate, pyruvate, and oxaloacetate. The time of the appearance of these compounds was used to propose the catabolic pathway [Kersten82].
In this pathway, the lactone, 2-pyrone-4,6-dicarboxylate, is hydrolyzed to the open chain keto form of the ring fission product. The enol tautomer, (1Z,3Z)-4-hydroxybuta-1,3-diene-1,2,4-tricarboxylate, can form spontaneously or enzymatically [Nogales10]. Hydration by a hydratase forms 4-carboxy-4-hydroxy-2-oxoadipate. This is cleaved to pyruvate and oxaloacetate by the aldolase. These 2 metabolites enter central metabolism, as indicated by the pathway link. These results demonstrated that Pseudomonas putida PDC can use enzymes of the meta fission pathway to degrade gallate [Kersten82, Tack72].
Unification Links: KEGG:MAP00360
Kersten82: Kersten PJ, Dagley S, Whittaker JW, Arciero DM, Lipscomb JD (1982). "2-pyrone-4,6-dicarboxylic acid, a catabolite of gallic acids in Pseudomonas species." J Bacteriol 1982;152(3);1154-62. PMID: 7142106
Nogales10: Nogales, J., Canales, A., Jimenez-barbero, J., Serra, B., Pingarron, J. M., Garcia, J. L., Diaz, E. (2010). "Unravelling the gallic acid degradation pathway in bacteria: the gal cluster from Pseudomonas putida." Molecular Microbiology, 79:359-374. PMID: 21219457
Bull81: Bull C, Ballou DP (1981). "Purification and properties of protocatechuate 3,4-dioxygenase from Pseudomonas putida. A new iron to subunit stoichiometry." J Biol Chem 256(24);12673-80. PMID: 6273403
Frazee93: Frazee RW, Livingston DM, LaPorte DC, Lipscomb JD (1993). "Cloning, sequencing, and expression of the Pseudomonas putida protocatechuate 3,4-dioxygenase genes." J Bacteriol 175(19);6194-202. PMID: 8407791
Hara00a: Hara H, Masai E, Katayama Y, Fukuda M (2000). "The 4-oxalomesaconate hydratase gene, involved in the protocatechuate 4,5-cleavage pathway, is essential to vanillate and syringate degradation in Sphingomonas paucimobilis SYK-6." J Bacteriol 182(24);6950-7. PMID: 11092855
Hara03: Hara H, Masai E, Miyauchi K, Katayama Y, Fukuda M (2003). "Characterization of the 4-carboxy-4-hydroxy-2-oxoadipate aldolase gene and operon structure of the protocatechuate 4,5-cleavage pathway genes in Sphingomonas paucimobilis SYK-6." J Bacteriol 185(1);41-50. PMID: 12486039
Maruyama01: Maruyama K, Miwa M, Tsujii N, Nagai T, Tomita N, Harada T, Sobajima H, Sugisaki H (2001). "Cloning, sequencing, and expression of the gene encoding 4-hydroxy-4-methyl-2-oxoglutarate aldolase from Pseudomonas ochraceae NGJ1." Biosci Biotechnol Biochem 65(12);2701-9. PMID: 11826967
Maruyama90: Maruyama K (1990). "Purification and properties of 4-hydroxy-4-methyl-2-oxoglutarate aldolase from Pseudomonas ochraceae grown on phthalate." J Biochem (Tokyo) 1990;108(2);327-33. PMID: 2229032
Masai99: Masai E, Shinohara S, Hara H, Nishikawa S, Katayama Y, Fukuda M (1999). "Genetic and biochemical characterization of a 2-pyrone-4, 6-dicarboxylic acid hydrolase involved in the protocatechuate 4, 5-cleavage pathway of Sphingomonas paucimobilis SYK-6." J Bacteriol 181(1);55-62. PMID: 9864312
Nogales05: Nogales J, Canales A, Jimenez-Barbero J, Garcia JL, Diaz E (2005). "Molecular characterization of the gallate dioxygenase from Pseudomonas putida KT2440: The prototype of a new subgroup of extradiol dioxygenases." J Biol Chem 280(42):35382-90. PMID: 16030014
Nogales11: Nogales J, Canales A, Jimenez-Barbero J, Serra B, Pingarron JM, Garcia JL, Diaz E (2011). "Unravelling the gallic acid degradation pathway in bacteria: the gal cluster from Pseudomonas putida." Mol Microbiol 79(2);359-74. PMID: 21219457
Providenti01: Providenti MA, Mampel J, MacSween S, Cook AM, Wyndham RC (2001). "Comamonas testosteroni BR6020 possesses a single genetic locus for extradiol cleavage of protocatechuate." Microbiology 147(Pt 8);2157-67. PMID: 11495993
Sparnins75: Sparnins VL, Dagley S (1975). "Alternative routes of aromatic catabolism in Pseudomonas acidovorans and Pseudomonas putida: gallic acid as a substrate and inhibitor of dioxygenases." J Bacteriol 124(3);1374-81. PMID: 1194238
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