A label-free electrochemical biosensor for methyltransferase activity detection and inhibitor screening based on graphene quantum dot and enzyme-catalyzed reaction

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Switzerland), 2017-08, Vol.799, p.327-332
• Main Authors: Peng, Xiaolun, Hu, Tianxing, Bao, Ting, Zhao, Lang, Zeng, Xi, Wen, Wei, Zhang, Xiuhua, Wang, Shengfu
• Format: Article
• Language: English
• Subjects: Amplification; Biosensors; Corrosion inhibitors; Deoxyribonucleic acid; DNA; Electrochemical biosensor; Enzyme-catalyzed reaction; Graphene; Graphene quantum dot; Hydrogen peroxide; Inhibitor screening; Methylation; Methyltransferase activity; Oxidation; Peroxidase; Recognition; Screening; Sensitivity analysis; Studies
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/j.jelechem.2017.06.030

A label-free electrochemical biosensor for methyltransferase (M.SssI MTase) activity detection and inhibitor screening was developed based on the amplification of graphene quantum dot (GQD) and enzyme-catalyzed reaction. In the construction of the electrochemical biosensor, auxiliary DNA hybridized with capture DNA to form the double-stranded DNA structure which contained a specific recognition sequence (5′-CCGG-3′) for both M.SssI MTase and restriction endonuclease HpaII. The presence of M.SssI MTase caused the methylation of CpG site in the ds-DNA, which could not be digested by HpaII, causing GQD bound to the undigested ds-DNA and acted as new platform for the immobilization of horseradish peroxidase (HRP) through noncovalant assembly. The modified HRP catalyzed the hydrogen peroxide-mediated oxidation of 3, 3′, 5, 5′-tetramethylbenzidine, resulting an electrochemical signal output. The proposed biosensor realized sensitivity detection of M.SssI MTase activity in the range of 1–40UmL−1 with a detection limit of 0.3UmL−1, and this dual-amplified biosensor had been successfully applied in M.SssI MTase activity inhibitor screening of procaine and epicatechin. Furthermore, this proposed strategy can also be extended for other methyltransferase detection, which had a promising application in clinical diagnosis and drug development. [Display omitted] •A label-free electrochemical biosensor of M.SssI MTase activity was developed.•GQD acted as novel platform for enzyme-catalyzed reaction.•The dual-amplified biosensor achieved sensitive M.SssI MTase activity detection.•The proposed biosensor realized inhibitor screening of M.SssI MTase activity.