Question

because nucleic acid synthesis is a common feature of all eukaryotic cells, it is generally a poor target for antifungal drugs. how is the drug flucytosine able to effectively target this process in yeast versus human cells?

Answer 1

Flucytosine is effective against fungal cells because it is converted by fungal-specific enzymes into a compound that disrupts DNA synthesis, whereas human cells lack these enzymes, making flucytosine selective and less toxic to humans.

Step-by-step explanation:

Flucytosine is an antifungal medication that targets nucleic acid synthesis in fungi such as yeast. Its efficacy in targeting yeast as opposed to human cells is due to its selective mechanism of action. The drug is taken up by fungal cells and converted by fungal-specific enzymes into a toxic compound that interferes with DNA synthesis. Human cells lack these specific enzymes, making flucytosine a poor substrate for conversion and therefore less toxic to human cells.

This selective toxicity makes flucytosine an effective antifungal drug despite the challenges in targeting eukaryotic cells without harming human cells. Furthermore, other antifungal drugs target ergosterol synthesis or cell wall components to exploit differences between fungal and human cells. These targets, such as ergosterol and chitin, are absent in human cells and provide a point of selective toxicity for antifungal treatments.