IDO1 is an indoleamine 2,3-dioxygenase - a heme enzyme that catalyzes the first and rate-limiting step in tryptophan catabolism to N-formyl-kynurenine. This enzyme acts on multiple tryptophan substrates including D-tryptophan, and serotonin. It 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 pericellular catabolization of the essential amino acid tryptophan. Source: Recombinant protein corresponding to aa1-403 from human IDO1, fused to His-Tag at N-terminal, expressed in E. coli. Molecular Weight: ~47.7 kD (426aa), confirmed by MALDI-TOF Endotoxin: <1EU/1ug (determined by LAL method) Biological Activity: Specific activity is >300pmol/min/ug, and is defined as the amount of enzyme that hydrolyze 1pmole of L-Tryptophan to N-formyl-L- kynurenine/minute at pH 6.5 at 25C. Amino Acid Sequence: MGSSHHHHHH SSGLVPRGSH MGSMAHAMEN SWTISKEYHI DEEVGFALPN PQENLPDFYN DWMFIAKHLP DLIESGQLRE RVEKLNMLSI DHLTDHKSQR LARLVLGCIT MAYVWGKGHG DVRKVLPRNI AVPYCQLSKK LELPPILVYA DCVLANWKKK DPNKPLTYEN MDVLFSFRDG DCSKGFFLVS LLVEIAAASA IKVIPTVFKA MQMQERDTLL KALLEIASCL EKALQVFHQI HDHVNPKAFF SVLRIYLSGW KGNPQLSDGL VYEGFWEDPK EFAGGSAGQS SVFQCFDVLL GIQQTAGGGH AAQFLQDMRR YMPPAHRNFL CSLESNPSVR EFVLSKGDAG LREAYDACVK ALVSLRSYHL QIVTKYILIP ASQQPKENKT SEDPSKLEAK GTGGTDLMNF LKTVRSTTEK SLLKEG Storage and Stability: May be stored at 4C for short-term only. Aliquot to avoid repeated freezing and thawing.. Store at -20C. Aliquots are stable for 6 months after receipt at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.