Measured by gel electrophoresis scanning,it was shown that the double strand breaks (DSBs) of pBR322 irradiated by γ rays were constituted by two parts,αDSB and βDSB,and the relationship between α,β and scavenging capacity σwas obtained.Results showed that β/α non linearly decreased with increasing σ.Moreover,the yield of the OH free radicals reacting with DNA was analyzed.
