An electrochemical assay for DNA methylation, methyltransferase activity and inhibitor screening based on methyl binding domain protein

► We develop a novel electrochemical method for MTase assay. ► Methyl binding domain protein was used as recognition unit of methylation site. ► Coomassie brilliant blue was used as electroactive label. ► A low detection limit of MTase was 0.04 unit/mL. ► This method provided information on screening of MTase inhibitor.