    1.13.11.11 | 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 |
743153 |
| 1.13.11.11 | L-tryptophan + O2 = N-formyl-L-kynurenine |
the dioxygenation reaction is initiated by a direct attack of O2 on the C2 atom of the L-Trp indole ring, catalytic mechanism, overview. Exo binding site for L-Trp, located about 42 A from the active site and formed by residues conserved among tryptophan-auxotrophic TDOs. Trp binding at this exo site does not affect enzyme catalysis but instead it retards the degradation of hTDO through the ubiquitin-dependent proteasomal pathway |
743821 |
