Nucleotide sequence cleavage of guanine-modified DNA with aflatoxin B1, dimethyl sulfate, and mitomycin C by bleomycin and deoxyribonuclease I.

In guanine-modified DNA with aflatoxin B1, dimethyl sulfate, and mitomycin C, the nucleotide sequence cleavage of bleomycin or DNase I has been investigated using 32P-labeled DNA fragments. In contrast with cis-dichlorodiammine platinum (II) which induces intrastrand crosslinking of guanine N7 atoms, these mono-covalent modifiers did not give remarkable alteration of the DNA nucleotide cleavage mode by bleomycin and DNase I. From the viewpoint of combination drug, it is of interest that mitomycin C promoted the DNA cleavage activity of bleomycin.