kynurenine/alpha-aminoadipate aminotransferase, mitochondrial; KAT/AadAT; 2-aminoadipate aminotransferase; 2-aminoadipate transaminase; alpha-aminoadipate aminotransferase; AadAT; kynurenine aminotransferase 2; kynurenine-oxoglutarate transaminase 2 (AADAT, KAT2)

Function

• lysine degradation via saccharopine pathway
  • glutaryl-CoA from L-lysine: step 4/6
• converts L-kynurenine to 4-(2-aminophenyl)-2,4-dioxobutanoate
• converts L-2-aminoadipate to 2-oxoadipate
• also shows activity also towards tryptophan, aspartate & hydroxykinurenine
• homodimer

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

L-2-aminoadipate + 2-oxoglutarate <--> 2-oxoadipate + L-glutamate

Cofactor: pyridoxal phosphate

Inhibition:

• kynurenine transaminase activity is competitively inhibited by aminoadipate, asparagine, glutamate, histidine, cysteine, lysine, 3-hydroxy-kynurenine & phenylalanine

Kinetic parameters:

• KM=0.9 mM for aminoadipate
• KM=4.7 mM for kynurenine
• KM=1.7 mM for methionine
• KM=1.6 mM for glutamate
• KM=1.8 mM for tyrosine
• KM=1.2 mM for 2-oxoglutarate
• KM=1.5 mM for 2-oxocaproic acid
• KM=1.8 mM for phenylpyruvate
• KM=1.4 mM for ino-3-pyruvate
• pH dependence: optimum pH is 7-9
• temperature dependence:
  • optimum temperature is 50 degrees celsius

Structure

• homodimer
• belongs to the class-I pyridoxal-phosphate-dependent aminotransferase family

Compartment

mitochondrion

Alternative splicing

named isoforms=2

Expression

• expressed in liver > heart, brain, kidney, pancreas, prostate, testis, ovary

More general terms

• aminotransferase
• mitochondrial protein
• oligomerizing protein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=51166
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:51166
• OMIM: https://mirror.omim.org/entry/611754
• UniProt: http://www.uniprot.org/uniprot/Q8N5Z0.html