Preparation method of recombinant NcoI restriction endonuclease

The invention provides a preparation method of a recombinant NcoI restriction enzyme, which comprises the following steps: 1, synthesizing NcoIM and NcoI coding genes, and respectively constructing the NcoIM and NcoI coding genes into corresponding vectors to obtain a recombinant vector with the NcoIM gene and an NcoI protein expression plasmid fused with a purification tag; 2, transferring the recombinant vector with the NcoIM gene into escherichia coli to obtain recombinant bacteria with substrate NcoIM expression; 3, preparing a recombinant bacterium competent cell with substrate NcoIM expression; 4, transferring the NcoI protein expression plasmid fused with the purification tag into a recombinant bacterium competent cell with substrate NcoIM expression to obtain positive monoclone, and culturing to express the NcoI restriction endonuclease; and 5, purifying the NcoI restriction endonuclease. Through the method provided by the invention, a large amount of NcoI restriction endonucleases can be obtained, an