The camptothecins are an alkaloid class of anticancer drugs used in the treatment of colon and breast cancers. These compounds function by inhibiting the activity of which of the following enzymes?
A) ATP-dependent DNA helicase
B) DNA ligase
C) DNA polymerase
D) histone deacetylase
E) topoisomerase I

Question

Quizplus · Accepted Answer

Camptothecins inhibit the activity of topoisomerase I, an enzyme crucial for DNA replication and transcription, by stabilizing the DNA-topoisomerase I complex, preventing the re-ligation of DNA strands and leading to DNA damage and cell death.  The camptothecins were originally found in the bark of the Camptotheca accuminata tree and include irinotecan (Campto, Camptosar) and topotecan (Hycamtin). Camptothecins inhibit the action of topoisomerase I, an enzyme that induces single-strand breaks in DNA during replication.

The Camptothecins Are an Alkaloid Class of Anticancer Drugs Used