The purpose of our study was to improve an evaluation system for DNA repair activity as one of
highlighted molecular pathways for the assessment of environment risk using DNA damage quantification
assay. Indeed, DNA repair has been able to use the molecular biomarker system of the environment
toxicity assessment with building the quantification assay system to detect AP damage site. In this study,
we focused on the optimization of DNA repair analysis in terms of the DNA purification, quantification
procedure, and treatment of DNA-damaging agents. Our data showed that the methods were hardly
different between DNA isolation kit and manual purification in RKO human colon cancer cells. In
addition, ARP solution concentration was optimized at 100μg/ml in ARP biding reaction. We observed
that AP site detection was saturated in the treatment of MMS at 100μM for more than 1 hour. Our
study provided the foundation of the novel toxicity assessment system to assay carcinogenic toxic
materials such as environmental hazard chemicals heavy metals. Furthermore, the improved assay system
for DNA repair might be one of useful for environmental health and cancer prevention.

Keywords: In vitro cell culture system, AP quantification assay, DNA damage