3-hydroxykynureninase activity
Definition
Target type: molecularfunction
Catalysis of the reaction: L-3-hydroxykynurenine + H2O = 3-hydroxyanthranilate + L-alanine. [PMID:17300176]
3-Hydroxykynureninase (EC 3.7.1.3) is a pyridoxal phosphate-dependent enzyme that catalyzes the hydrolytic cleavage of 3-hydroxykynurenine to alanine and 3-hydroxyanthranilate. This reaction is a key step in the kynurenine pathway, which is a major route of tryptophan catabolism in mammals. 3-hydroxykynureninase is a member of the α-amino acid racemase superfamily and shares a common structural motif with other pyridoxal phosphate-dependent enzymes, such as kynureninase and alanine racemase. The active site of the enzyme contains a pyridoxal phosphate cofactor that is essential for catalysis. The mechanism of the reaction involves the formation of a Schiff base intermediate between the pyridoxal phosphate cofactor and the amino group of 3-hydroxykynurenine. This Schiff base is then hydrolyzed to release alanine and 3-hydroxyanthranilate. 3-hydroxykynureninase activity is essential for the proper function of the kynurenine pathway and is therefore involved in a variety of physiological processes, including the biosynthesis of nicotinamide adenine dinucleotide (NAD+), the regulation of immune responses, and the protection against oxidative stress.'
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Proteins (1)
| Protein | Definition | Taxonomy |
|---|---|---|
| Kynureninase | A kynureninase that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q16719] | Homo sapiens (human) |
Compounds (3)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| 3-hydroxykynurenine | 3-hydroxykynurenine : A hydroxykynurenine that is kynurenine substituted by a hydroxy group at position 3. 3-hydroxykynurenine: RN given refers to cpd without isomeric designation hydroxykynurenine : A hydroxy-amino acid that is kynurenine substituted by a single hydroxy group at unspecified position. A "closed" class. | hydroxykynurenine | human metabolite |
| kynurenine | L-kynurenine : A kynurenine that has L configuration. | amino acid zwitterion; kynurenine; non-proteinogenic L-alpha-amino acid | human metabolite; mouse metabolite; Saccharomyces cerevisiae metabolite |
| 3-hydroxyhippuric acid | 3-hydroxyhippuric acid: a kynureninase inhibitor; structure in first source m-hydroxyhippuric acid : An N-acylglycine that is hippuric acid (N-benzoylglycine) substituted at position 3 on the phenyl ring by a hydroxy group. | N-acylglycine; phenols | metabolite |