Kynurenine 3-monooxygenase is an

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

that in humans is encoded by the ''KMO''

gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...

. Kynurenine 3-monooxygenase (KMO; EC 1.14.13.9) is an NADPH-dependent flavin monooxygenase that catalyzes the hydroxylation of the L-

tryptophan Tryptophan (symbol Trp or W) is an α-amino acid that is used in the biosynthesis of proteins. Tryptophan contains an α-amino group, an α-carboxylic acid group, and a side chain indole, making it a polar molecule with a non-polar aromatic ...

metabolite L-

kynurenine -Kynurenine is a metabolite of the amino acid -tryptophan used in the production of niacin. Kynurenine is synthesized by the enzyme tryptophan dioxygenase, which is made primarily but not exclusively in the liver, and indoleamine 2,3-dioxygenase ...

to form L-3-hydroxykynurenine. upplied by OMIMref name="entrez"/> This is the first step in the degradation of Kyneurinine to

Quinolinic acid Quinolinic acid (abbreviated QUIN or QA), also known as pyridine-2,3-dicarboxylic acid, is a dicarboxylic acid with a pyridine backbone. It is a colorless solid. It is the biosynthetic precursor to niacin. Quinolinic acid is a downstream produc ...

. This pathway is involved in the activation of cytokine mediated changes in behavior due to inflammatory stimuli such as infections. The KMO gene is upregulated in the lung parenchyma of smokers.

References

Further reading