DECREASE OF MELTING TEMPERATURE AND SINGLE STRAND SCISSION OF DNA BY BLEOMYCIN IN THE PRESENCE OF HYDROGEN PEROXIDE

Abstract

Effect of bleomycin and H₂O₂ on DNA was investigated. Tm of salmon sperm DNA decreased from 76°C to 64°C and that of Escherichia coli DNA from 81°C to 65.5°C in the presence of 100μM of H₂O₂ and 4μg/ml of bleomycin. The change of Tm was more marked when the concentration of H₂O₂ or bleomycin was increased. The single strand scission of DNA was shown when the DNA was incubated at 37°C with 100μM of H₂O₂ and 40μg/ml of bleomycin. It proceeded as the time of incubation was prolonged. The reaction of H₂O₂ at 100μM on DNA was apparent only in the presence of bleomycin.