Label-free monitoring of site-specific DNA cleavage by EcoRI endonuclease using cyclic voltammetry and electrochemical impedance

Cyclic voltammetry (CV) combined with electrochemical impedance spectroscopy (EIS) were proposed to monitor the site-specific DNA cleavage by EcoRI endonuclease without using external label. The alteration of CV and EIS signal demonstrated that double-strands (dsDNA) contain recognition sequence was cleaved by EcoRI endonuclease. Real-time monitoring indicated that the dsDNA was cleaved by EcoRI more than 90% after 2 h of enzyme digestion time. Control experiment showed that the DNA cleavage by EcoRI endonuclease is site-specific for DNA sequence. Experimental results demonstrated that the efficiency of EcoRI cleavage was highly dependent on the concentration of EcoRI concentration in the range from 0.04 to 0.4 U mu L(-1) with one almost linear relationship. (C) 2008 Elsevier B.V. All rights reserved.