摘要：O6-Methylguanine (O6-MeGua), formed in calf thymus DNA by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or N-methyl-N-nitrosourea (MNU) in vitro was determined by high-performance liquid chromatography (HPLC) with electrochemical detection. The DNA treated with MNNG or MNU was hydrolyzed to nucleic bases under a mild acidic condition. O6-MeGua was separated from abundant normal adenine and guanine bases with a Sep-Pak C18 cartridge prior to HPLC analysis. With the cartridge, the peak areas of adenine and guanine bases decreased less than 0.3% as compared to those without clean-up process, although the recovery of O6-MeGua through the clean-up process was more than 96%. The amount of O6-MeGua formed from 1μg of DNA treated with 7.3 nmol of MNNG and 14.7 nmol of MNU was 9.66 and 11.1 pmol, respectively.
