Activating Compound | Comment | Organism | Structure |
---|---|---|---|
ascorbate | promotes IDO peroxidase turnover by reducing Compound II | Homo sapiens | |
hydrogen peroxide | activates the peroxidase function of IDO to induce protein oxidation and inhibit dioxygenase activity | Homo sapiens | |
additional information | L-Trp is a poor reductant of IDO compound II | Homo sapiens |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
cyanide | inhibits the dioxygenase activity | Homo sapiens | |
H2O2 | inhibits the dioxygenase activity in a manner abrogated by L-Trp. Physiological peroxidase substrates, ascorbate or tyrosine, enhanced rIDO-mediated H2O2 consumption and attenuated H2O2-induced protein oxidation and dioxygenase inhibition. H2O2 alters the heme active site of recombinant IDO | Homo sapiens | |
additional information | the dioxygenase enzyme activity is inhibited by free radical scavengers. Protection of the dioxygenase enzyme function by L-Trp coincides with its oxidation into oxindolylalanine and kynurenine and the formation of a compound II-type ferryl-oxo heme | Homo sapiens |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Fe2+ | heme-containing enzyme, reduction of heme from the ferric (FeIII) to the ferrous (FeII) form facilitates binding of O2 and L-Trp to form the active ternary complex | Homo sapiens |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
additional information | Homo sapiens | the enzyme acts as a heme peroxidase that, in the absence of substrates, self-inactivates dioxygenase activity via compound I-initiated protein oxidation. L-Trp protects against dioxygenase inactivation by reacting with compound I and retarding compound II reduction to suppress peroxidase turnover. Catalytic cycle of hemeperoxidase enzymes, and enzyme peroxidase mechanism, overview | ? | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Homo sapiens | - |
- |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
additional information | the enzyme acts as a heme peroxidase that, in the absence of substrates, self-inactivates dioxygenase activity via compound I-initiated protein oxidation. L-Trp protects against dioxygenase inactivation by reacting with compound I and retarding compound II reduction to suppress peroxidase turnover. Catalytic cycle of hemeperoxidase enzymes, and enzyme peroxidase mechanism, overview | Homo sapiens | ? | - |
? |
Synonyms | Comment | Organism |
---|---|---|
IDO | - |
Homo sapiens |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
37 | - |
assay at | Homo sapiens |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
7.4 | - |
assay at | Homo sapiens |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
heme | the active-site heme is essential for IDO dioxygenase activity, reduction of heme from the ferric (FeIII) to the ferrous (FeII) form facilitates binding of O2 and L-Trp to form the active ternary complex | Homo sapiens |
General Information | Comment | Organism |
---|---|---|
additional information | H2O2 activates the peroxidase function to induce protein oxidation and inhibit dioxygenase activity, overview. Dioxygenase inhibition correlated with IDO-catalyzed H2O2 consumption, compound I-mediated formation of protein-centered radicals, altered protein secondary structure, and opening of the distal heme pocket to promote nonproductive substrate binding, inhibited by L-Trp, the heme ligand cyanide, or free radical scavengers | Homo sapiens |
physiological function | heme enzyme indoleamine 2,3-dioxygenase is a key regulator of immune responses through catalyzing L-tryptophan oxidation. Peroxidase-mediated dioxygenase inactivation, NO consumption, or protein nitration may modulate the biological actions of IDO expressed in inflammatory tissues where the levels of H2O2 and NO are elevated and L-Trp is low | Homo sapiens |