RNA/DNA Polymerase

RNA and DNA polymerase inhibitors block enzymes that copy nucleic acid templates in bacteria, viruses and human cells. Rifampin and rifabutin are rifamycins that bind bacterial RNA polymerase and stop the transcript after two or three nucleotides. For RNA viruses, favipiravir serves as a prodrug whose triphosphate form blocks the viral RNA-dependent RNA polymerase. Tenofovir and abacavir block reverse transcriptase, the DNA polymerase of human immunodeficiency virus (HIV). Actinomycin D intercalates into DNA and blocks transcription, and BMH-21 inhibits RNA polymerase I. Fludarabine phosphate, a purine nucleoside analog, inhibits the human DNA polymerases α and δ.