3'-azido-3'-deoxythymidine (AZT) monophosphate: an inhibitor of exonucleolytic repair of AZT-terminated DNA.

Abstract A 3'-exonuclease(s) that excised 3'-azido-3'-deoxythymidine (AZT) monophosphate (AZTMP) from the 3' terminus of DNA was partially purified from two human cell lines. AZTMP inhibited the hydrolysis of AZTMP-terminated single-stranded and double-stranded DNA substrates. Thus, high levels of AZTMP might inhibit the exonuclease and trigger the toxicity of AZT by impairing the repair of AZTMP-terminated DNA.