Induction of single strand scission in bacteriophage .PHI.X174 replicative form I DNA by mitomycin C.

Abstract
The action of mitomycin C on double-stranded replicative form I DNA (RF I DNA; supercoiled, covalently closed, circular duplex DNA) of bacteriophage .vphi.X174 was investigated using the technique of agarose gel electrophoresis. Mitomycin C reduced with sodium hydrosulfite (sodium dithionite, Na2S2O4) caused single strand scission in .vphi.X174 RF I DNA in the presence of Cu2+. Cu2+ was essential for this DNA cleavage action, and other transition metal ions such as Fe2+, Fe3+, Mn2+, Co2+ and Zn2+ were of no effect. This DNA strand scission was inhibited by catalase (EC 1.11.1.6) and various radical scavengers. This DNA strand scission was caused by free oxygen radicals generated during autoxidation of reduced mitomycin C in the presence of Cu2+.