Primary structure of human indoleamine 2,3-dioxygenase deduced from the nucleotide sequence of its cDNA.

Indoleamine 2,3-dioxygenase (IDO), a tryptophan degrading length and encodes a protein containing 403 residues and having enzyme, is induced by interferons (IFNs) (1, 2). As a first step a molecular weight of 45,324. towards elucidating the mechanism of IDO induction by IFN's, we report here the primary structure of human IDO deduced from sequences of cDNA clones. These clones were isolated from a Xgtl 1 library prepared from poly (A) + RNA of IFN-y -treated HEL cells (Flow 2000) with a monoclonal antibody against IDO. The predicted amino acid sequence contained partial amino acid sequences (underlined letters) of endopeptidic digests of purified IDO protein. The open reading frame is 1209 nucleotides in