TDO2 (NM_005651) Human Recombinant Protein

This gene encodes a heme enzyme that plays a critical role in tryptophan metabolism by catalyzing the first and rate-limiting step of the kynurenine pathway. Increased activity of the encoded protein and subsequent kynurenine production may also play a role in cancer through the suppression of antitumor immune responses, and single nucleotide polymorphisms in this gene may be associated with autism. [provided by RefSeq, Feb 2012]

The specific activity of TDO2 was determined by monitoring Kynurenine formation from the N-formylkynurenine based on the absorbance at 492nm. The N-formylkynurenine was produced from a conversion of tryptophan with TDO2. The reactions were carried out at 37°C for 40min in 100ul of the reaction volume containing 200mM PBS, pH7.5, 1mM ascorbic acid, and 1.25mM L-tryptophan as the substrate with various amounts of TDO2. The reaction was terminated by adding 50ul of 30% (w/v) trichloroacetic acid. The sample was further incubated for 30min at 60°C and centrifuged at 12000 rpm for 15 min. The supernatant was used to mix with an equal volume of Ehrlich's reagent (2% p-dimethylaminobenza-ldehyde in glacial acetic acid) to measure the absorbance at 492 nm after 10min incubation

Stable for 1 year at -20°C or below from date of shipment. For maximum recovery of product, centrifuge the original vial after thawing and opening the cap. For long-term storage, aliquot and store at -20°C or below. Avoid repeated freeze-thaw cycles.