2-Aminomuconic acid
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| Preferred IUPAC name
(2Z,4E)-2-Aminohexa-2,4-dienedioic acid | |
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CompTox Dashboard (EPA)
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| Properties | |
| C6H7NO4 | |
| Molar mass | 157.12 g/mol |
| Density | 1.461 g/mL |
| Boiling point | 368.4 °C (695.1 °F; 641.5 K) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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2-Aminomuconic acid (also known as 2-aminomuconate) is an unsaturated dicarboxylic amino acid. It serves as a biochemical intermediate in the microbial degradation of various aromatic compounds and is involved in the oxidative cleavage steps of the kynurenine pathway of tryptophan catabolism.
Structure and basic properties
[edit]2-Aminomuconic acid is a six-carbon molecule bearing two carboxyl groups, two conjugated double bonds, and a primary amino substituent at carbon 2. The neutral formula is C6H7NO4. The molecule is commonly encountered in its ionized form, 2-aminomuconate, under physiological and environmental aqueous conditions.[1]
Specific physical constants such as pKa values, solubility, and spectroscopic data are not comprehensively tabulated in the primary literature and should be added only with a verified source.
Occurrence and metabolic context
[edit]2-Aminomuconic acid is observed in two general biological contexts:
In microbial biodegradation of aromatic xenobiotics, for example certain nitroaromatic compounds, where ring-cleavage pathways produce aminomuconic intermediates prior to further downstream processing. The compound appears as a catabolic intermediate in several bacterial strains studied under laboratory conditions.[1]
In the oxidative degradation of tryptophan via the kynurenine pathway, intermediates with structural relation to aminomuconate are formed during enzymatic ring opening and aldehyde oxidation steps.[2] For example, aminomuconate-semialdehyde dehydrogenase is the enzyme that catalyzes a chemical reaction which uses nicotinamide adenine dinucleotide (NAD+) as its cofactor:[3]
Wherever it appears, the ionized form 2-aminomuconate is typically the biologically relevant species.[citation needed]
Biosynthesis and enzymology
[edit]In enzymatic schemes described in the literature:
- The immediate precursor known in many pathways is 2-aminomuconate semialdehyde, which can be oxidized to 2-aminomuconate by aldehyde dehydrogenase activity. Human ALDH8A1 has been reported to accept related substrates in the kynurenine pathway context.[2]
- Bacterial pathways include enzymes that catalyze ring cleavage and subsequent deamination or dehydrogenation reactions. A 2-aminomuconate deaminase activity has been reported in bacterial isolates that degrade nitrobenzene derivatives; this enzyme converts 2-aminomuconate to downstream catabolites such as 4-oxalocrotonate, releasing ammonium in the process.
Details such as kinetic constants, mechanism and gene names vary by organism and strain and should be cited from the primary enzymology literature for each specific claim.
Environmental and applied relevance
[edit]In environmental microbiology, pathways involving 2-aminomuconate are part of bacterial systems that allow mineralization of aromatic pollutants, converting recalcitrant compounds into metabolites that join central carbon metabolism. Such pathways are of interest for biodegradation and bioremediation research.[1]
See also
[edit]References
[edit]- ^ a b c He, Z.; Nishino, S. F. (1997). "Complete mineralization of 2,4,6-trinitrotoluene in liquid medium by a bacterial consortium". Applied and Environmental Microbiology. 63 (7): 2704–2709. doi:10.1128/aem.63.7.2925-2927.1997. PMC 168588. PMID 16535658.
- ^ a b Davis, Ian; Yang, Yu; Wherritt, Daniel; Liu, Aimin (2018). "Reassignment of the human aldehyde dehydrogenase ALDH8A1 (ALDH12) to the kynurenine pathway in tryptophan catabolism". Journal of Biological Chemistry. 293 (25): 9594–9603. doi:10.1074/jbc.RA118.003320. PMC 6016481. PMID 29703752.
- ^ Ichiyama A, Nakamura S, Kawai H, Honjo T, Nishizuka Y, Hayaishi O, Senoh S (February 1965). "Studies on the metabolism of the benzene ring of tryptophan in mammalian tissues. II. enzymic formation of alpha-aminomuconic acid from 3-hydroxyanthranilic acid". The Journal of Biological Chemistry. 240 (2): 740–9. doi:10.1016/S0021-9258(17)45238-0. PMID 14275130.