Tryptophan 2,3-dioxygenase

In enzymology, a tryptophan 2,3-dioxygenase is an enzyme that catalyzes the chemical reaction


 * L-tryptophan + O2 $$\rightleftharpoons$$ N-formyl-L-kynurenine

Thus, the two substrates of this enzyme are L-tryptophan and O2, whereas its product is N-formyl-L-kynurenine.

This enzyme belongs to the family of oxidoreductases, specifically those acting on single donors with O2 as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases). The oxygen incorporated need not be derived from O2. The systematic name of this enzyme class is L-tryptophan:oxygen 2,3-oxidoreductase (decyclizing). Other names in common use include tryptophan pyrrolase (ambiguous), tryptophanase, tryptophan oxygenase, tryptamine 2,3-dioxygenase, tryptophan peroxidase, indoleamine 2,3-dioxygenase (ambiguous), indolamine 2,3-dioxygenase (ambiguous), L-tryptophan pyrrolase, TDO, and L-tryptophan 2,3-dioxygenase. This enzyme participates in tryptophan metabolism. It employs one cofactor, heme.

Structural studies
As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes and.