Cytosolic deoxycytidylate deaminase (DCTD) catalyzes the hydrolysis of dCMP (2'-deoxyuridine 5'-monophosphate) to yield dUMP (2'-deoxyuridine 5'-monophosphate) and ammonia. The active enzyme is a homohexamer (Maley et al. 1993; Weiner et al. 1993; unpublished crystallography data - PDB 2W4L).