IUBMB Enzyme Nomenclature


Accepted name: single-stranded DNA cytosine deaminase

Reaction: cytosine in single-stranded DNA + H2O = uracil in single-stranded DNA + NH3

Other name(s): AID; activation-induced deaminase; AICDA (gene name); activation-induced cytidine deaminase

Systematic name: single-stranded DNA cytosine aminohydrolase

Comments: 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: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:


1. Sohail, A., Klapacz, J., Samaranayake, M., Ullah, A. and Bhagwat, A.S. Human activation-induced cytidine deaminase causes transcription-dependent, strand-biased C to U deaminations. Nucleic Acids Res. 31 (2003) 2990-2994. [PMID: 12799424]

2. Larijani, M., Petrov, A.P., Kolenchenko, O., Berru, M., Krylov, S.N. and 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 (2007) 20-30. [PMID: 17060445]

3. Brar, S.S., Sacho, E.J., Tessmer, I., Croteau, D.L., Erie, D.A. and Diaz, M. Activation-induced deaminase, AID, is catalytically active as a monomer on single-stranded DNA. DNA Repair (Amst.) 7 (2008) 77-87. [PMID: 17889624]

4. Larijani, M. and Martin, A. Single-stranded DNA structure and positional context of the target cytidine determine the enzymatic efficiency of AID. Mol. Cell Biol. 27 (2007) 8038-8048. [PMID: 17893327]

5. Verma, S., Goldammer, T. and Aitken, R. Cloning and expression of activation induced cytidine deaminase from Bos taurus. Vet. Immunol. Immunopathol. 134 (2010) 151-159. [PMID: 19766322]

[EC created 2013]

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