Abstract
Poly (2-methylthioinosinic acid) [poly(ms2I)] was found to markedly inhibit the RNA directed DNA polymerase (reverse transcriptase) activity of murine (Moloney, Rauscher) leukemia virus and murine (Moloney) sarcoma virus, while under the same conditions the unsubstituted parent compound poly(I) showed little, if any, inhibitory effect. Copolymers of inosinic acid (I) and 2-methylthioinosinic acid2(ms2I) showed an intermediary effect, depending on the I:ms2I ratio. Poly(ms2I) also inhibited the transformation of normal cells by murine (Moloney) sarcoma virus, as assessed by an infectious center assay.