5-Fluorouracil is utilized as a chemotherapeutic agent because of its ability to interfere with the function of which of the following enzymes?

Question

Quizplus · Accepted Answer

5-Fluorouracil is a pyrimidine analog that inhibits thymidylate synthase, an enzyme crucial for DNA synthesis, thereby exerting its chemotherapeutic effects.  Tetrahydrofolate (THF) is regenerated from the dihydrofolate (DHF) product of the thymidylate synthase reaction by the action of dihydrofolate reductase (DHFR). Cells that are unable to regenerate THF suffer defective DNA synthesis and eventual death. For this reason, it is therapeutically possible to target rapidly proliferating cells over nonproliferating cells through the inhibition of thymidylate synthase. A class of molecule used to inhibit thymidylate synthase is called the suicide substrates because they irreversibly inhibit the enzyme. Molecules of this class include 5-fluorouracil and 5-fluorodeoxyuridine. Both are converted within cells to 5-fluorodeoxyuridylate (FdUMP). It is this drug metabolite that inhibits thymidylate synthase.

5-Fluorouracil Is Utilized as a Chemotherapeutic Agent Because of Its