Methylene blue cation → 1H-Indolamine

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Reaction Steps

Human indoleamine 2,3-dioxygenasae (IDO) with an N-terminal H is tag was expressed in E. coli and purified to homogeneity. IDO catalyzes the oxidative cleavage of the pyrrole ring of the indole nucleus of tryptophan to yield N′-formylkynurenine. The assays were performed at room temperature as described in the literature using 95 nM IDO and 2 mM D-Trp in the presence of 20 mM ascorbate, 5 μM methylene blue and 0.2 mg/mL catalase in 50 mM potassium phosphate buffer (pH 6.5). The initial reaction rates were recorded by continuously following the absorbance increase at 321 nm due to the formation of N′-formylkynurenine. See: Sono, M., Taniguchi, T., Watanabe, Y., and Hayaishi, O. (1980) J. Biol. Chem. 255, 1339-1345 Compounds of the invention having an IC50 less than about 100 μM were considered active.

Provenance & Evidence