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Literature summary for extracted from

  • Nienhaus, K.; Hahn, V.; Huepfel, M.; Nienhaus, G.U.
    Substrate binding primes human tryptophan 2,3-dioxygenase for ligand binding (2017), J. Phys. Chem. B, 121, 7412-7420 .
    View publication on PubMed

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
additional information
additional information reaction and ligand binding kinetics, two hTDO conformations exist that bind CO in a bimolecular reaction, but with very different rates, kinetic calculations, overview Homo sapiens


Metals/Ions Comment Organism Structure
Fe2+ ferric heme Homo sapiens

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
L-tryptophan + O2 Homo sapiens


Organism UniProt Comment Textmining
Homo sapiens P48775


Reaction Comment Organism Reaction ID
L-tryptophan + O2 = N-formyl-L-kynurenine catalytic mechanism, modeling. hTDO exists as two discrete species with markedly different ligand binding properties. The active site environment of the slowly rebinding species is structurally very heterogeneous and ligand access to greatly hindered. Binding of the L-Trp substrate stabilizes the faster-binding species, which features a well-structured active site and offers facile access of the ligand to the heme iron. This mechanism ensures that the ternary complex forms mainly by first binding the L-Trp substrate, which primes the active site for the subsequent binding of O2, which ensures efficient enzyme action Homo sapiens

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
L-tryptophan + O2
Homo sapiens N-formyl-L-kynurenine
additional information enzyme-CO binding analysis, overview Homo sapiens ?


Synonyms Comment Organism
Homo sapiens

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
assay at Homo sapiens


Cofactor Comment Organism Structure
heme ferric heme Homo sapiens

General Information

General Information Comment Organism
additional information the active site of the enzyme is highly dynamic Homo sapiens
physiological function the human heme enzyme tryptophan 2,3-dioxygenase (hTDO) catalyzes the insertion of dioxygen into its cognate substrate, L-tryptophan (L-Trp) Homo sapiens