dCMP Deaminase (DCTD)

DCTD catalyzes the deamination of dCMP to dUMP, the nucleotide substrate for thymidylate synthase. The encoded protein is allosterically activated by dCTP and inhibited by dTTP, and is found as a homohexamer. This protein uses zinc as a cofactor for its activity. Two transcript variants encoding different isoforms have been found for this gene.

The deduced 178-amino acid protein has a calculated molecular mass of about 20 kD and contains a zinc-binding region similar to that in cytidine deaminase. Northern blot analysis revealed a single transcript of 1.9 kb expressed in HeLa cells.DCTD exhibited dCMP deaminase activity comparable to that of the endogenous enzyme purified from HeLa cells.