EFFECTS OF BLEOMYCIN A₂ ON DEOXYRIBONUCLEASE, DNA POLYMERASE AND LIGASE REACTIONS

Abstract

Bleomycin A₂ caused degradation of DNA in the intact cells of E. coli 15T^- and stimulated breakdown of DNA by DNase in the crude extract of E. coli B. On the other hand, the incorporation of dGMP into acid-insoluble fraction by partially purified E. coli B DNA polymerase was stimulated by bleomycin A₂ for a short period after the addition of the antibiotic, and thereafter degradation of the product was observed. Digestion of salmon sperm DNA by pancreatic DNase was also stimulated by the antibiotic. An inhibitory effect of bleomycin A₂ on polynucleotide ligase prepared from T₄ phage-infected E. coli B was observed. The above in vivo and in vitro effects of bleomycin A₂ can be explained if it causes strand scission of DNA. The stimulation of DNase reaction may also be related to the DNA strand scission by bleomycin.