Inhibition of eucaryotic DNA polymerases by phosphonoacetate and phosphonoformate

Phosphonoacetate was found to be an inhibitor of the DNA polymerase α from three human cells, HeLa, Wi-38, and phytohemagglutinin-stimulated lymphocytes. The inhibition patterns were determined. The apparent inhibition constants ( K ii) were about 30 μ m. Thus the DNA polymerase α is 15 to 30 times less sensitive to Phosphonoacetate than the herpesvirus-induced DNA polymerase. The DNA polymerase α from Chinese hamster ovary cells and calf thymus was also inhibited. The DNA polymerases β and γ from the eucaryotic cells were relatively insensitive to phosphonoacetate. The sensitivity of the DNA polymerase α and the relative insensitivity of the DNA polymerase β and γ appeared to be general characteristics of the vertebrate polymerases, DNA polymerases from two other eucaryotic cells, yeast DNA polymerase A and B and tobacco cell DNA polymerase, were inhibited by phosphonoacetate, and to about the same extent as the α-polymerases. Fourteen phosphonate analogs were examined for inhibition of the HeLa DNA polymerase α. Only one, phosphonoformate, was an inhibitor. The mechanism of inhibition for phosphonoformate was analogous to that for phosphonoacetate.