Cytosine deaminase (CD) catalyses the deamination of cytosine to uracil and ammonia. It is an enzyme produced by bacteria and yeast, but not mammalian cells, and is a potential gene therapy agent. CD deaminates 5-fluorocytosine to potent antimetabolite 5-fluorouracil, which can block DNA replication in cells. Bacterial CD (bCD) is capable of deaminating a wide range of cytosine derivatives with varying efficiency. It is dependent of Fe2+ for maximal catalytic activity.
Defined by 6 residues: HIS:A-65 [auth A-61]HIS:A-67 [auth A-63]GLN:A-160 [auth A-156]HIS:A-218 [auth A-214]GLU:A-221 [auth A-217]ASP:A-317 [auth A-313]