"Indoleamine 2,3-dioxygenase 1 (IDO1) catalyzes the first and rate-limiting step in tryptophan catabolism to N-formyl-kynurenine. This enzyme is thought to play a role in a variety of pathophysiological processes such as antimicrobial and antitumor defense, neuropathology, immunoregulation, and antioxidant activity. Through its
expression in dendritic cells, monocytes, and macrophages this enzyme modulates T-cell behavior by its peri-cellular catabolization of the essential amino acid tryptophan.
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