An electrochemical method to assay human 8-oxoguanine DNA glycosylase 1

Abstract Human 8-oxoguanine DNA glycosylase 1 (hOGG1) is an important DNA repair enzyme that can excise the 8-oxo-7,8-dihydroguanine (8-oxoG) from damaged DNA and is implicated in the etiology of many kinds of cancers. Here, we report an electrochemical method to assess the activity of hOGG1 by using a carefully designed DNA probe, which contains an internal 8-oxoG site and an electrochemical active tag. In this method, hOGG1 can selectively recognize the 8-oxoG site and cleave the probe DNA, releasing a methylene blue (MB)-labeled signal fragment. The signal fragment can then hybridize with the DNA molecules that have been previously immobilized on a gold electrode surface. Consequently, a sensitive electrochemical technique, square wave voltammetry, can be employed for the signal readout, thus characterizing the activity of hOGG1. This method is simple, sensitive and specific, and it has been used for human serum samples, so it may imply a potential new method for the assay of hOGG1.