EC - Single-stranded DNA cytosine deaminase

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IntEnz Enzyme Nomenclature


Accepted name:
single-stranded DNA cytosine deaminase
Other names:
activation-induced deaminase
AICDA (gene name)
activation-induced cytidine deaminase
Systematic name:
single-stranded DNA cytosine aminohydrolase



The enzyme exclusively catalyses deamination of cytosine in single-stranded DNA. It preferentially deaminates five-nucleotide bubbles. The optimal target consists of a single-stranded NWRCN motif (W = A or T, R = A or G) [2]. The enzyme initiates antibody diversification processes by deaminating immunoglobulin sequences.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
UniProtKB/Swiss-Prot: (16) [show] [UniProt]


  1. Sohail, A., Klapacz, J., Samaranayake, M., Ullah, A., Bhagwat, A. S.
    Human activation-induced cytidine deaminase causes transcription-dependent, strand-biased C to U deaminations.
    Nucleic Acids Res. 31: 2990-2994 (2003). [PMID: 12799424]
  2. Larijani, M., Petrov, A. P., Kolenchenko, O., Berru, M., Krylov, S. N., Martin, A.
    AID associates with single-stranded DNA with high affinity and a long complex half-life in a sequence-independent manner.
    Mol. Cell. Biol. 27: 20-30 (2007). [PMID: 17060445]
  3. Brar, S. S., Sacho, E. J., Tessmer, I., Croteau, D. L., Erie, D. A., Diaz, M.
    Activation-induced deaminase, AID, is catalytically active as a monomer on single-stranded DNA.
    DNA Repair (Amst.) 7: 77-87 (2008). [PMID: 17889624]
  4. Larijani, M., Martin, A.
    Single-stranded DNA structure and positional context of the target cytidine determine the enzymatic efficiency of AID.
    Mol. Cell. Biol. 27: 8038-8048 (2007). [PMID: 17893327]
  5. Verma, S., Goldammer, T., Aitken, R.
    Cloning and expression of activation induced cytidine deaminase from Bos taurus.
    Vet. Immunol. Immunopathol. 134: 151-159 (2010). [PMID: 19766322]

[EC created 2013]