Cytosine deaminase (Escherichia coli) (CD or CDA)

Cytosine deaminase from Escherichia coli is a microbial enzyme that catalyzes the conversion of cytosine to uracil, which is a key reaction in the pyrimidine salvage pathway, allowing the microorganism to utilize cytosine as a nitrogen source. The enzyme is structurally characterized by an (αβ)\_8\_ barrel fold, contains a catalytic metal ion (usually iron), and is not present in multicellular eukaryotes[1][2]. Cytosine deaminase has gained attention in biotechnology and medicine because it enables tumors engineered to express it to convert the antifungal prodrug 5-fluorocytosine into the anticancer agent 5-fluorouracil, resulting in a localized cytotoxic effect for cancer gene therapy ("suicide gene" approach)[5][1]. In addition to cytosine, the enzyme can also deaminate mutagenic bases such as isoguanine[3]. It is not a human protein, reducing the risk of immune tolerance and conferring specificity in targeted applications.

Other names

cytosine aminohydrolasebCD (bacterial cytosine deaminase)codA (gene)Escherichia coli cytosine deaminase

Hydrolytic deamination of cytosine to uracil; Bioactivation of 5-fluorocytosine to cytotoxic 5-fluorouracil for use in suicide gene therapy[5][6][2]