"The processing of the lesions was evaluated by purified enzyme cocktails of hNTH1 and hOGG1 as well as with a HeLa cell extract. Interestingly the yield of double-strand breaks (DSBs) resulting from the processing of the bistranded lesions are appreciably lower when the DNA is treated with the HeLa cell extract compared with the relevant purified enzyme cocktail in both models"xsd:string