The Indolamine 2,3-Dioxygenase 1 (IDO1) Activity Assay Kit (ab235936) enables the easy determination of IDO1 activity in mammalian tissues and cell lines. The assay uses a fluorogenic developer that selectively reacts with N-formylquinurenine (NFK) to produce a highly fluorescent product (Ex / Em = 402/88 nm), ensuring a high signal/background ratio.
The kit also includes a highly selective IDO1 inhibitor for the verification of enzymatic activity in biological matrices. The assay has a simple no-wash protocol, is adaptive, high throughput, and can detect up to 0.2 mU of IDO1 activity or 200 pmol of NFK.
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Indoleamine 2,3-Dioxygenase 1 (IDO1, EC 1.13.11.52) is a cytoplasmatic hemoprotein that oxidizes tryptophan yielding N-formylkynurenine (NFK). In mammals, this reaction is the first and rate-limiting step in the kynurenine catabolic pathway. IDO1 activity is low under normal physiological conditions but is dramatically upregulated by proinflammatory cytokines such as interferon-γ.
This short-term activation of IDO1 occurs as part of the innate immune response and helps to inhibit the growth of pathogens and parasites. IDO1 activation can also promote host immunotolerance by exerting an immunosuppressive effect. IDO1 expression by tumor cells plays a susbtancial role in tumor immune tolerance, aiding tumors in evading detection and destruction.
Chronic induction of IDO1 expression has been found in cancer patients increased IDO1 activity is correlated with a negative prognosis. IDO1 has thus become an attractive pharmacological target for the development of novel antineoplastics and adjuvants to increase the efficacy of conventional chemotherapy.