This enzyme scavenges exogenous and endogenous cytidine and 2'-deoxycytidine for UMP synthesis. cytidine + H(+) + H2O = NH4(+) + uridine 2'-deoxycytidine + H(+) + H2O = 2'-deoxyuridine + NH4(+) Homotetramer. Highly expressed in granulocytes while expression is very low in fibroblasts, chondrocytes, monocytes, and T- as well as B-cell lines. Belongs to the cytidine and deoxycytidylate deaminase family.