Kynurenine—oxoglutarate transaminase

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kynurenine-oxoglutarate transaminase
Kynurenine aminotransferase-I homodimer, Human
EC no.
CAS no.9030-38-0
IntEnzIntEnz view
ExPASyNiceZyme view
MetaCycmetabolic pathway
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO

In enzymology, a kynurenine-oxoglutarate transaminase (EC is an enzyme that catalyzes the chemical reaction

L-kynurenine + 2-oxoglutarate ⇌ 4-(2-aminophenyl)-2,4-dioxobutanoate + L-glutamate

Thus, the two substrates of this enzyme are L-kynurenine and 2-oxoglutarate, whereas its two products are 4-(2-aminophenyl)-2,4-dioxobutanoate and L-glutamate. The former product is an unstable α-oxo acid that quickly undergoes intramolecular cyclization to form kynurenic acid.[1]

This enzyme belongs to the family of transferases, to be specific, the transaminases, that transfer nitrogenous groups. The systematic name of this enzyme class is L-kynurenine:2-oxoglutarate aminotransferase. Other names in common use include kynurenine transaminase (cyclizing), kynurenine 2-oxoglutarate transaminase, kynurenine aminotransferase, and L-kynurenine aminotransferase. This enzyme participates in tryptophan metabolism. It employs one cofactor, pyridoxal phosphate.

KYAT1, AADAT (aka KYAT2), and KYAT3 are examples of enzymes of this class. GOT2 (aka KYAT4) is also believed to catalyze the above reaction.[2]

Structural studies[edit]

As of early 2009, 18 structures have been solved for this class of enzymes, with PDB accession codes 1X0M, 1YIY, 1YIZ, 1W7L, 1W7M, 1W7N, 3E2F, 3E2Y, 3E2Z, 2ZJG, 2YGZ, 2Z61, 2R5C, 2R2N, 2R5E, 3B46, 3DC1, and 2QLN.


  1. ^ Han Q, Cai T, Tagle DA, Robinson H, Li J (August 2008). "Substrate specificity and structure of human aminoadipate aminotransferase/kynurenine aminotransferase II". Bioscience Reports. 28 (4): 205–15. doi:10.1042/BSR20080085. PMC 2559858. PMID 18620547.
  2. ^ Guidetti P, Amori L, Sapko MT, Okuno E, Schwarcz R (July 2007). "Mitochondrial aspartate aminotransferase: a third kynurenate-producing enzyme in the mammalian brain". Journal of Neurochemistry. 102 (1): 103–11. doi:10.1111/j.1471-4159.2007.04556.x. PMID 17442055. S2CID 20413002.

Further reading[edit]