Inhibition of HIV-1 RNA-dependent DNA polymerase and cellular DNA polymerases α, β and γ by phosphonoformic acid and other drugs

Potential specific inhibitors of HIV RNA-dependent DNA polymerase (RDDP) were examined in an in-vitro test system containing purified HIV-1 RDDP, or functionally purified cellular DNA-dependent DNA polymerases alpha, beta and gamma. A wide variety of drugs were tested for their specific inhibitory activity against the viral enzyme to identify substances which, at the same concentration, did not inhibit the cellular DNA polymerases. Phosphonoformic acid and derivatives were found to be the most specific inhibitors, followed by chlortetracycline.