The Sound of Evolution
Flucytosine
Mechanism of action:
Flucytosine is a pyrimidine nucleoside analog. Flucytosine enters fungal cells through the fungus-specific cytosine permease and is then converted by cytosine deaminase into 5-fluorouracil, which is further converted into 5-fluorouridine triphosphate (FUTP) and 5-fluorodeoxyuridylate. 5-fluorouridine triphosphate can be mistakenly incorporated into RNA, leading to abnormal protein synthesis, while 5-fluorodeoxyuridylate inhibits thymidylate synthase and blocks the production of dTMP required for DNA synthesis.
Reference(s):
1. Osterman DG et al. (1988). 5-Fluorocytosine in DNA is a mechanism-based inhibitor of HhaI methylase. Biochemistry.
2. Waldorf AR et al. (1983). Mechanisms of action of 5-fluorocytosine. Antimicrob Agents Chemother.
3. Wyszynski MW et al. (1993). The cysteine conserved among DNA cytosine methylases is required for methyl transfer, but not for specific DNA binding. Nucleic Acids Res.