Human cysteine dioxygenase type I: primary structure derived from base sequencing of cDNA

The base sequence of cDNA encoding the complete human liver cysteine dioxygenase type I (CDO-I; EC 1.13.11.20) message, and the derived amino-acid sequence are reported. CDO-I is encoded on a single mRNA species (approx. 1.5 kb). Human CDO-I clones were identified by screening a liver cDNA library, and inserts were isolated and sequenced. In addition, human liver total RNA was reverse-transcribed and CDO-I cDNA amplified by PCR using a modified poly-T primer and specific CDO-I primers to give a second source of sequencing template. The CDO-I message encodes a 200 amino-acid residue protein, the sequence of which has greater than 90% homology with the equivalent rat enzyme. The message was not expressed in a human hepatoma cell line (Hep G2).