<unk> -pyrrole 2,3-dioxygenase <unk>  or INDO ) is a heme-containing enzyme physiologically expressed in a number of tissues and cells, such as the small intestine, lungs, female genital tract or placenta. In humans is encoded by the<unk> 1 gene.<unk>  is involved in tryptophan metabolism. It is one of three enzymes that catalyze the first and rate-limiting step in the kynurenine pathway, the O2-dependent oxidation of L-tryptophan to N-formylkynurenine, the others being<unk> -2,3-dioxygenase 2 <unk> 2) and tryptophan 2,3-dioxygenase (TDO).<unk>  is an important part of the immune system and plays a part in natural defense against various pathogens. It is produced by the cells in response to inflammation and has an immunosuppressive function because of its ability to limit T-cell function and engage mechanisms of immune tolerance. Emerging evidence suggests that<unk>  becomes activated during tumor development, helping malignant cells escape eradication by the immune system. Expression of<unk>  has been described in a number of types of cancer, such as acute myeloid leukemia, ovarian cancer or colorectal cancer.<unk>  is part of the malignant transformation process and plays a key role in suppressing the anti-tumor immune response in the body, so inhibiting it could increase the effect of chemotherapy as well as other immunotherapeutic protocols.
Indoleamine 2,3-dioxygenase
Prostaglandin-endoperoxide synthase 2
Angiotensin-converting enzyme 2
Iduronate-2-sulfatase
Monoamine oxidase A
Flavin-containing monooxygenase 3
Aromatic L-amino acid decarboxylase
Monoamine oxidase B