A protohemoprotein. In mammals, the enzyme appears to be located only in the liver. This enzyme, together with EC 1.13.11.52, indoleamine 2,3-dioxygenase, catalyses the first and rate-limiting step in the kynurenine pathway, the major pathway of tryptophan metabolism . The enzyme is specific for tryptophan as substrate, but is far more active with L-tryptophan than with D-tryptophan .
A protohemoprotein. In mammals, the enzyme appears to be located only in the liver. This enzyme, together with EC 1.13.11.52, indoleamine 2,3-dioxygenase, catalyses the first and rate-limiting step in the kynurenine pathway, the major pathway of tryptophan metabolism [5]. The enzyme is specific for tryptophan as substrate, but is far more active with L-tryptophan than with D-tryptophan [2].
the enzyme has broad substrate specificity for various indoleamines such as L-tryptophan and serotonin. It catalyzes the oxidation of the pyrrole ring of tryptophan to form N-formylkynurenine, which is later metabolized to formic acid and kynurenine
in mouse liver homogenate, TDO activity is five times lower for D-Trp than that for L-Trp. L-Trp is the preferred substrate for nicotinamide synthesis because L-Trp metabolism is more efficient than D-Trp in mice
in mouse liver homogenate, TDO activity is five times lower for D-Trp than that for L-Trp. L-Trp is the preferred substrate for nicotinamide synthesis because L-Trp metabolism is more efficient than D-Trp in mice
comparison of contribution percentage of tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO, EC 1.13.11.52) to the conversion of L-tryptophan, the calculated percentage conversions indicats that TDO and IDO oxidize 70% and 30%, respectively, of the dietary L-tryptophan. The amount of D-Trp converted to nicotinamide via indole-3-pyruvic acid (IPA) is very low, this amount of D-Trp is converted to L-Trp, which is primarily used for protein synthesis rather than catabolism via the Kyn biosynthesis pathway in mice
the enzyme is involved in nicotinamide biosynthesis. Comparison of contribution percentage of tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO, EC 1.13.11.52) to the conversion of L-tryptophan, the calculated percentage conversions indicats that TDO and IDO oxidize 70% and 30%, respectively, of the dietary L-tryptophan. The amount of D-Trp converted to nicotinamide via indole-3-pyruvic acid (IPA) is very low, this amount of D-Trp is converted to L-Trp, which is primarily used for protein synthesis rather than catabolism via the Kyn biosynthesis pathway in mice
Maeta, A.; Sano, M.; Fukuwatari, T.; Funakoshi, H.; Nakamura, T.; Shibata, K.
Contributions of tryptophan 2,3-dioxygenase and indoleamine 2,3-dioxygenase to the conversion of D-tryptophan to nicotinamide analyzed by using tryptophan 2,3-dioxygenase-knockout mice