Human TDO2 Alexa Fluor™ Plus 555‑conjugated Antibody

Tryptophan 2,3-dioxygenase (TDO2), a heme-containing cytosolic dioxygenase, forms a homo-tetrameric active molecule of approximately 190 kDa composed of 48 kDa monomers (1, 2). Human TDO2 shares 89% aa sequence identity with mouse TDO2. TDO2 is one of three proteins capable of catalyzing the first and rate‑limiting step of the L-kynurenine pathway (KP): oxidative cleavage of the essential amino acid L-tryptophan to form N‑formyl‑kynurenine (3). TDO2 is a cytosolic protein typically localized to the liver and brain, unlike the more ubiquitously expressed indoleamine 2,3-dioxygenase (IDO), yet it is responsible for ~90% of the primary route of catabolism of tryptophan through the KP (3). TDO2 is upregulated in extrahepatic tumors (4-6) and is consequently a target in cancer immunotherapy (7). TDO2 is a therapeutic target in brain disease such as schizophrenia, Alzheimers disease, multiple sclerosis and glioma (8-11) due to its role in the regulation of levels of critical biologically active downstream KP metabolites (3). Polymorphisms in the TDO2 gene have been implicated for a role in behavioural responses and autism (12,13).