IDO1 (human, recombinant)

Indoleamine 2,3-dioxygenase 1 (IDO1) is a cytosolic heme-containing enzyme involved in tryptophan catabolism that mediates multiple immunomodulatory processes.^1,2 It exists as a monomer and is composed of a large catalytic domain, which contains the heme group, and a small non-catalytic domain with two immunoreceptor tyrosine-based inhibition motifs (ITIMs) that regulate intracellular signaling.^3,4 IDO1 catalyzes the oxidation of L-tryptophan (Item No. 29600) to N-formylkynurenine, the first and rate-limiting step of the kynurenine pathway, leading to the production of several metabolites of kynurenine (Item No. 11305), including 3-hydroxy anthranilic acid (Item No. 20512), that have immunoprotective and immunosuppressive effects.¹ IDO1 is widely expressed in several lymphoid and non-lymphoid organs, including lymph nodes, spleen, tonsils, lungs, and intestine, as well as immune cells, including macrophages and dendritic cells (DCs), and endothelial cells.¹ IDO1 activity is regulated at the transcriptional level where expression of IDO1 is increased by the transcription factors NF-κB, aryl hydrocarbon receptor (AhR), and CCTF, which are induced by stimulation with toll-like receptor (TLR) ligands or cytokines and inhibited by hypoxia.¹ IDO1 activity can also be inhibited at the protein level by peroxynitrite (Item No. 81565), leading to IDO1 inactivation, or suppressor of cytokine signaling 3 (SOCS3), which binds to and targets IDO1 for proteasomal degradation. Increased IDO1 activity is associated with numerous pathological conditions, including atherosclerosis, autoimmunity, HIV, and cancer. Cayman's IDO1 (human, recombinant) protein can be used for enzyme assay applications. This protein consists of 402 amino acids and has a calculated molecular weight of 46 kDa.

WARNING This product is not for human or veterinary use.

1. Hornyák, L., Dobos, N., Koncz, G., et al. The role of indoleamine-2,3-dioxygenase in cancer development, diagnostics, and therapy. Front. Immunol. 9, 151 (2018).

2. Röhrig, U.F., Majjigapu, S.R., Vogel, P., et al. Challenges in the discovery of indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors. J. Med. Chem. 58(24), 9421-9437 (2015).

3. Coletti, A., Greco, F.A., Dolciami, D., et al. Advances in indoleamine 2,3-dioxygenase 1 medicinal chemistry. Med. Chem. Commun. 8(7), 1378-1392 (2017).

4. Cheong, J.E., and Sun, L. Targeting the IDO1/TDO2–KYN–AhR pathway for cancer immunotherapy – challenges and opportunities. Trends Pharmacol. Sci. 39(3), 307-325 (2018).