title: An electrochemical one-step system for assaying methyltransferase activity based on transport of a quantum dot signaling tracer.
abstract: A one-step, electrochemical method for assaying methyltransferase (MTase) activity, based on the convective transport of a quantum dot (QD) signaling tracer, has been developed. The assay chip used in this system was prepared by modifying a gold matrix with CdSe/ZnS QD-tagged dsDNA, which contains a specific methylation site (5'-GATC-3') recognized by MTase. Treatment of the chip with DNA adenine methylation (Dam) MTase, generates a methylated sequence (5'-GAmTC-3') within the dsDNA. The methylated dsDNA is then subjected to a cleavage reaction, induced by DpnI, which leads to release from the gold matrix of a DNA fragment tethered to a QD. Detection of the released QD, using square wave anodic stripping voltammetry (SWASV) on a glassy carbon (GC) electrode, enables the reliable quantitation of the methylated DNA. Because it is accomplished in a simple and convenient one step and does not require any complicated secondary or tedious washing steps, the new assay method holds great promise for epigenetic analysis in facility-limited environments or point-of-care testing (POCT) applications.
authors.affiliation: Department of Chemical and Biomolecular Engineering (BK21 Program), KAIST, Daejeon 305-701, Republic of Korea.
authors.forename: Songyi
authors.initials: S
authors.lastname: Baek
authors.forename: Byoung Yeon
authors.initials: BY
authors.lastname: Won
authors.forename: Ki Soo
authors.initials: KS
authors.lastname: Park
authors.forename: Hyun Gyu
authors.initials: HG
authors.lastname: Park
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D015374:Biosensing Techniques / Q000379:methods; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D019175:DNA Methylation; D015254:DNA Modification Methylases / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism*; D055664:Electrochemical Techniques / Q000379:methods*; D057075:Enzyme Assays / Q000379:methods; D006801:Humans; D057230:Limit of Detection; D045663:Quantum Dots
chemical_list: D000970:Antineoplastic Agents; D004247:DNA; D015254:DNA Modification Methylases
keywords: DNA methylation; Electrochemical biosensor; Epigenetic analysis; Methyltransferase; Quantum dot