Antagonism of the cytotoxic but not antiviral effects of ara-sangivamycin by adenosine.

Inhibition of DNA synthesis by ara-sangivamycin was antagonized by adenosine. The 50% inhibitory concentrations increased 1.6- to 32-fold in the presence of 1.0 to 50 microM adenosine, respectively. In contrast, the inhibition of human cytomegalovirus replication by ara-sangivamycin was not antagonized by as much as 50 microM adenosine. This suggests that different enzymes were responsible for the phosphorylation of ara-sangivamycin in uninfected and infected cells.