Kynurenine—oxoglutarate transaminase

kynurenine-oxoglutarate transaminase
Identifiers
EC number 2.6.1.7
CAS number 9030-38-0
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / QuickGO

In enzymology, a kynurenine-oxoglutarate transaminase (EC 2.6.1.7) 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

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.

References

  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 (Jul 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.
  • BONNER DM, JAKOBY WB (1956). "Kynurenine transaminase from neurospora". J. Biol. Chem. 221 (2): 689&ndash, 95. PMID 13357462.
  • MASON M (1957). "Kynurenine transaminase of rat kidney; a study of coenzyme dissociation". J. Biol. Chem. 227 (1): 61&ndash, 8. PMID 13449053.
  • Rossi F.; Han Q.; Li J.; Li J.; Rizzi M. (2004). "Crystal structure of human kynurenine aminotransferase I". J. Biol. Chem. 279 (48): 50214–20. doi:10.1074/jbc.M409291200. PMID 15364907.
  • Chon H.; Matsumura H.; Koga Y.; Takano K.; Kanaya S. (2005). "Crystal structure of a human kynurenine aminotransferase II homologue from Pyrococcus horikoshii OT3 at 2.20 A resolution". Proteins. 61 (3): 685–8. doi:10.1002/prot.20614. PMID 16138312.
  • Han Q.; Gao Y.G.; Robinson H.; Ding H.; Wilson S.; Li J. (2005). "Crystal structures of Aedes aegypti kynurenine aminotransferase". FEBS J. 272 (9): 2198–206. doi:10.1111/j.1742-4658.2005.04643.x. PMID 15853804.
  • Han Q.; Robinson H.; Cai T.; Tagle D.A.; Li J. (2009). "Biochemical and structural properties of mouse KAT III". Mol Cell Biol. 29 (3): 784–93. doi:10.1128/MCB.01272-08. PMC 2630683. PMID 19029248.
  • Han Q.; Robinson H.; Li J. (2008). "Crystal structure of human kynurenine aminotransferase II". J. Biol. Chem. 283 (6): 3567–73. doi:10.1074/jbc.M708358200. PMID 18056995.
  • Rossi F.; Garavaglia S.; Montalbano V.; Walsh M.A.; Rizzi M. (2008). "Crystal structure of human kynurenine aminotransferase II, a drug target for the treatment of schizophrenia". J. Biol. Chem. 283 (6): 3559–66. doi:10.1074/jbc.M707925200. PMID 18056996.
  • Han Q.; Cai T.; Tagle D.A.; Robinson H.; Li J. (2008). "Substrate specificity and structure of human aminoadipate aminotransferase/kynurenine aminotransferase II". Biosci Rep. 28 (4): 205–15. doi:10.1042/BSR20080085. PMC 2559858. PMID 18620547.
  • Han Q.; Gao Y.G.; Robinson H.; Li J. (2008). "Structural insight into the mechanism of substrate specificity of aedes kynurenine aminotransferase". Biochemistry. 47 (6): 1622–30. doi:10.1021/bi701800j. PMC 2858008. PMID 18186649.
  • Wogulis M.; Chew E.R.; Donohoue P.D.; Wilson D.K. (2008). "Identification of formyl kynurenine formamidase and kynurenine aminotransferase from Saccharomyces cerevisiae using crystallographic, bioinformatic and biochemical evidence". Biochemistry. 47 (6): 1608–21. doi:10.1021/bi701172v. PMID 18205391.


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