A Novel Fluorescence Assay for the Activity of Restriction Endonuclease Based on Molecular Beacon

A novel and simple fluorescence assay for the activity of XspⅠ restriction endonuclease was proposed based on molecular beacons cutting by restriction endonuclease. The temporary and dynamic double DNA structure was suggested as the possible cleavage mechanism. Under the optimal condition,the initial velocity was proportional to the concentration of endonuclease in the range of 0.05 to 50U/mL and the detection limit was 0.05 U/mL. This method can also be extended to other restriction endonucleases, such as AluⅠ,by changing the reorganization sequence in the loop part of MB(Molecular Beacon,MB).