The Effect of a Protein on the Radiolysis of DNA Studied by Gel Filtration

Summary

Double stranded DNA from calf thymus was irradiated in the presence of bovine serum albumin with a ratio of 1 : 10 in weight under aerobic and anaerobic conditions. The irradiated biomolecules were separated by gel filtration on Sepharose C1-2B with and without sodium dodecylsulphate. By scavenging OH-radicals the protein protects DNA, but in contrast to radiolysis of DNA in phosphate buffer, in the presence of serum albumin oxygen enhances the degradation of DNA. Radiolysis under N₂ leads to crosslinking of serum albumin to DNA with higher yields at pH 5 than at pH 7. Oxygen largely prevents crosslinking.

• radiolysis
• DNA
• DNA-protein crosslinking
• gel filtration