RT Journal Article SR Electronic T1 Fragmentation of Deoxyribonucleic Acid by Bleomycin JF Molecular Pharmacology JO Mol Pharmacol FD American Society for Pharmacology and Experimental Therapeutics SP 645 OP 652 VO 7 IS 6 A1 HAIDLE, CHARLES W. YR 1971 UL http://molpharm.aspetjournals.org/content/7/6/645.abstract AB The ability of the antibiotic bleomycin to cause single- as well as double-strand breaks in deoxyribonucleic acid in vitro has been confirmed. Heat-denatured, single-stranded DNA is considerably more sensitive to the action of bleomycin than is native DNA. The rate of the reaction of DNA breakage by bleomycin is enhanced in the presence of 2-mercaptoethanol; however, 2-mercaptoethanol also inactivates bleomycin. This inactivation reaction is especially rapid at 80°, although bleomycin itself is stable to heating at 100° for 10 min. Bleomycin alone causes the fragmentation of DNA upon prolonged incubation, and therefore the presence of the reducing agent is not obligatory. In the presence of high concentrations of bleomycin, the DNA is degraded to the level of free nucleotides, nucleosides, or bases. ACKNOWLEDGMENTS The author wishes to thank Miss Kay Weiss and Mrs. Elsie Jackson for their excellent technical assistance.