A New Assay for Endonuclease/Methyltransferase Activiities Based on Graphene Oxide

A new endonuclease/methyltransferase activity assay method based on graphene oxide (GO) is developed. Substrate DNA is designed to possess a double-stranded part to serve as a nuclease substrate and a single-stranded part for anchoring the DNA to the GO surface via strong noncovalent binding. Nuclease-mediated DNA hydrolysis induces the recovery of fluorescence intensity of the dye attached to the end of the double-stranded DNA region. This GO-based method allows real-time measurement and quantitative assay for endonuclease/methyltransferase activities in short time.