The antibacterial activity of a new nucleoside antibiotic, 2'-amino-2'-deoxyguanosine (2AG), is reversed by guanosine and other purine nucleosides. 2AG is apparently taken up by E. coliby a mechanism different from that of guanosine; guanosine inhibits this uptake non-competitively. Insensitive E. colistrains and the resistant mutant obtained from the sensitive strain also took up 2AG.
