Formation of a phosphoramide mustard-nucleotide adduct that is not by alkylation at the N7 position of guanine.

The reaction of 2'-deoxyguanosine 3'-monophosphate with phosphoramide mustard resulted in the formation of several adducts. One of these adducts was formed by linking phosphoramide mustard to the phosphate group of 2'-deoxyguanosine 3'-monophosphate rather than by the generally accepted mechanism involving alkylation at the N7 position of guanine. This adduct served as an acceptor for the transfer of 32p from [gamma 32P]ATP by polynucleotide kinase and thus could be detected by the sensitive 32p-postlabeling assay.