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The Sound of Evolution
Flucytosine
氟胞嘧啶
Mechanism of action:
Flucytosine 是一種嘧啶核苷（pyrimidine nucleoside）類似物。Flucytosine 透過真菌特有的胞嘧啶通透酶（cytosine permease）進入真菌細胞，之後被胞嘧啶去胺酶（cytosine deaminase）轉化為 5-氟尿嘧啶（5-fluorouracil），再轉化為 5-氟尿苷三磷酸（5-fluorouridine triphosphate，FUTP）和 5-氟去氧尿苷酸（5- fluorodeoxyuridylate）。5-氟尿苷三磷酸能被錯誤摻入 RNA，造成蛋白質合成異常；5-氟去氧尿苷酸則能抑制胸苷酸合成酶（thymidylate synthase），阻斷 DNA 合成所需的 dTMP 生成。
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.
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