Single-stranded DNA-specific cytidine deaminase. Involved in somatic hypermutation, gene conversion, and class- switch recombination in B-lymphocytes. Required for several crucial steps of B-cell terminal differentiation necessary for efficient antibody responses. May also play a role in the epigenetic regulation of gene expression by participating in DNA demethylation. Strongly expressed in lymph nodes and tonsils. Belongs to the cytidine and deoxycytidylate deaminase family. Note: This description may include information from UniProtKB.