KynurenineKynurenine 3-Monooxygenase: An NADPH-dependent flavin monooxygenase that plays a key role in the catabolism of TRYPTOPHAN by catalyzing the HYDROXYLATION of KYNURENINE to 3-hydroxykynurenine. It was formerly characterized as EC 22.214.171.124 and EC 126.96.36.199.Tryptophan: An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals.Indoleamine-Pyrrole 2,3,-Dioxygenase: A dioxygenase with specificity for the oxidation of the indoleamine ring of TRYPTOPHAN. It is an extrahepatic enzyme that plays a role in metabolism as the first and rate limiting enzyme in the kynurenine pathway of TRYPTOPHAN catabolism.Tryptophan Oxygenase: A dioxygenase with specificity for the oxidation of the indoleamine ring of TRYPTOPHAN. It is a LIVER-specific enzyme that is the first and rate limiting enzyme in the kynurenine pathway of TRYPTOPHAN catabolism.Kynurenic Acid: A broad-spectrum excitatory amino acid antagonist used as a research tool.Arylformamidase: An enzyme that catalyzes the conversion of N-formyl-L-kynurenine and water to formate and L-kynurenine. It also acts on other aromatic formylamines. (Enzyme Nomenclature, 1992) EC 188.8.131.52.Quinolinic Acid: A metabolite of tryptophan with a possible role in neurodegenerative disorders. Elevated CSF levels of quinolinic acid are correlated with the severity of neuropsychological deficits in patients who have AIDS.Transaminases: A subclass of enzymes of the transferase class that catalyze the transfer of an amino group from a donor (generally an amino acid) to an acceptor (generally a 2-keto acid). Most of these enzymes are pyridoxyl phosphate proteins. (Dorland, 28th ed) EC 184.108.40.206-Hydroxyanthranilic Acid: An oxidation product of tryptophan metabolism. It may be a free radical scavenger and a carcinogen.Xanthurenates2-Aminoadipate Transaminase: A PYRIDOXAL PHOSPHATE containing enzyme that catalyzes the transfer of amino group of L-2-aminoadipate onto 2-oxoglutarate to generate 2-oxoadipate and L-GLUTAMATE.ortho-Aminobenzoates: Benzoic acids, salts, or esters that contain an amino group attached to carbon number 2 or 6 of the benzene ring structure.Hydrolases: Any member of the class of enzymes that catalyze the cleavage of the substrate and the addition of water to the resulting molecules, e.g., ESTERASES, glycosidases (GLYCOSIDE HYDROLASES), lipases, NUCLEOTIDASES, peptidases (PEPTIDE HYDROLASES), and phosphatases (PHOSPHORIC MONOESTER HYDROLASES). EC 3.Lyases: A class of enzymes that catalyze the cleavage of C-C, C-O, and C-N, and other bonds by other means than by hydrolysis or oxidation. (Enzyme Nomenclature, 1992) EC 4.Amination: The creation of an amine. It can be produced by the addition of an amino group to an organic compound or reduction of a nitro group.