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 → Amines and Polyamines Degradation → Allantoin Degradation|
Allantoin is a common product of purine degradation. Allantoin is rich in nitrogen, and many organisms are able to degrade and recycle it. Some bacteria, including Bacillus fastidiosus, Delftia acidovorans and Ralstonia eutropha JMP134, do so under aerobic conditions, while others such as Escherichia coli K-12, Streptococcus allantoicus and Providencia rettgeri do so only anaerobically.
Allantoin degradation is not limited to bacteria. Ureide-transporting plants convert fixed nitrogen in their roots to allantoin and allantoate, which are then transported to upper parts of the plant, where they are degraded to release the nitrogen. In addition, some fungi and animals also degrade allantoin.
The first step of the pathway, catalyzed by allantoinase, comprises the hydrolysis of the internal amide bond of (S)-(+)-allantoin, forming allantoate [Vogels76]. This enzyme turned out to be common to all organisms that can degrade allantoin, and is the first step in all allantoin degradation pathways.
Allantoate is converted to S-ureidoglycolate via one of two routes. In the first route the nitrogen is liberated in a single step in the form of urea (EC 22.214.171.124), while in the other route it is liberated in the form of ammonia in two steps, via the intermediate a (-)-ureidoglycine (starting with EC 126.96.36.199).
Several combinations of these routes have been documented. Some organisms possess pathways that produce solely urea (see allantoin degradation to glyoxylate I), some produce only ammonia (see allantoin degradation to glyoxylate II), and some produce both (see allantoin degradation to glyoxylate III). In addition, some anaerobic organisms can degrade allantoin to oxalurate instead of glyoxylate (see allantoin degradation IV (anaerobic)).
About This Pathway
In this hybrid pathway allantoate amidohydrolase monomer and ureidoglycine aminohydrolase catalyze the first two steps, producing S-ureidoglycolate and ammonia, while ureidoglycolate lyase gives rise to glyoxylate and urea. This pathway has been clearly documented in enterobacteria, including Escherichia coli K-12 [Cusa99, Serventi10], and some other bacteria, such as Bacillus fastidiosus [Xu95a]. There has been an ongoing debate regarding which pathway(s) operate in plants, but some research suggests that the hybrid pathway may exist in Glycine max and Phaseolus vulgaris [Todd04, Raso07].
Variants: allantoin degradation IV (anaerobic) , allantoin degradation to glyoxylate I , allantoin degradation to glyoxylate II , allantoin degradation to ureidoglycolate I (urea producing) , superpathway of allantoin degradation in plants , superpathway of allantoin degradation in yeast
Unification Links: EcoCyc:PWY-5705
Cusa99: Cusa E, Obradors N, Baldoma L, Badia J, Aguilar J (1999). "Genetic analysis of a chromosomal region containing genes required for assimilation of allantoin nitrogen and linked glyoxylate metabolism in Escherichia coli." J Bacteriol 1999;181(24);7479-84. PMID: 10601204
Raso07: Raso MJ, Munoz A, Pineda M, Piedras P (2007). "Biochemical characterisation of an allantoate-degrading enzyme from French bean (Phaseolus vulgaris): the requirement of phenylhydrazine." Planta 226(5);1333-42. PMID: 17594111
Serventi10: Serventi F, Ramazzina I, Lamberto I, Puggioni V, Gatti R, Percudani R (2010). "Chemical basis of nitrogen recovery through the ureide pathway: formation and hydrolysis of S-ureidoglycine in plants and bacteria." ACS Chem Biol 5(2);203-14. PMID: 20038185
Agarwal07: Agarwal R, Burley SK, Swaminathan S (2007). "Structural analysis of a ternary complex of allantoate amidohydrolase from Escherichia coli reveals its mechanics." J Mol Biol 368(2);450-63. PMID: 17362992
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
Kim00a: Kim GJ, Lee DE, Kim HS (2000). "Functional expression and characterization of the two cyclic amidohydrolase enzymes, allantoinase and a novel phenylhydantoinase, from Escherichia coli." J Bacteriol 2000;182(24);7021-8. PMID: 11092864
Munoz01: Munoz A, Piedras P, Aguilar M, Pineda M (2001). "Urea Is a Product of Ureidoglycolate Degradation in Chickpea. Purification and Characterization of the Ureidoglycolate Urea-Lyase." Plant Physiol 2001;125(2);828-834. PMID: 11161040
Munoz06: Munoz A, Raso MJ, Pineda M, Piedras P (2006). "Degradation of ureidoglycolate in French bean (Phaseolus vulgaris) is catalysed by a ubiquitous ureidoglycolate urea-lyase." Planta 224(1);175-84. PMID: 16333637
Percudani13: Percudani R, Carnevali D, Puggioni V (2013). "Ureidoglycolate hydrolase, amidohydrolase, lyase: how errors in biological databases are incorporated in scientific papers and vice versa." Database (Oxford) 2013;bat071. PMID: 24107613
Puggioni14: Puggioni V, Dondi A, Folli C, Shin I, Rhee S, Percudani R (2014). "Gene context analysis reveals functional divergence between hypothetically equivalent enzymes of the purine-ureide pathway." Biochemistry 53(4);735-45. PMID: 24417435
Rintoul02: Rintoul MR, Cusa E, Baldoma L, Badia J, Reitzer L, Aguilar J (2002). "Regulation of the Escherichia coli allantoin regulon: coordinated function of the repressor AllR and the activator AllS." J Mol Biol 324(4);599-610. PMID: 12460564
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