Protein—DNA Crosslinks Induced by Primary and Secondary Radicals

Summary

Double-stranded DNA from calf thymus was irradiated in the presence of bovine serum albumin (BSA) at a ratio of 1:10 by mass under air, N₂ or N₂O, with and without ethanol, tert-butanol or isopropanol in 10⁻² mol dm⁻³ sodium phosphate buffer, pH 7·0. The irradiated solutions were analysed by a nitrocellulose filter assay and by high-performance liquid gel chromatography. The results show that OH^· radicals as well as hydrated electrons induce protein—DNA crosslinks. Further, alcohol radicals react with BSA producing protein radicals which become crosslinked to DNA. If OH radicals are scavenged by alcohol, strand breakage of DNA does not occur.