%0 Journal Article %A Chan, Emerson W. %A Lee, Chung K. %A Dale, Phylis J. %A Nortridge, Kimberly R. %A Hom, Sophia S. %A Seed, Thomas M. %T Antiviral Properties of Polyinosinic Acids containing Thio and Methyl Substitutions %D 1981 %J Journal of General Virology, %V 52 %N 2 %P 291-299 %@ 1465-2099 %R https://doi.org/10.1099/0022-1317-52-2-291 %I Microbiology Society, %X SUMMARY Polyinosinic acids containing methyl and sulphur substitutions are potent inhibitors of reverse transcriptase. Substitution of sulphur for oxygen at the 6 position produces significant effects on the properties of polyinosinic acid: the kinetics of inhibition change from competitive to mixed-type and the inhibition constant falls by three orders of magnitude. In contrast, 1-methyl substitution produces no such effects. Poly(1-methyl-6-thioinosinic acid) or poly(m1s6I) inhibits irreversibly, inhibiting all ten reverse transcriptases tested under a variety of assay conditions. In cell culture test systems, poly(m1s6I) is capable of blocking both infection by non-transforming viruses and transformation by a sarcoma virus. The presence of poly(m1s6I) in a preinfected culture results in the production of non-infectious virus particles lacking reverse transcriptase activity. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-52-2-291