With the rapid progress of science and technology, enzymes in our life of the use is more and more widely. Restriction enzymes also play a important role in our life. Restriction end nuclease is a special nucleotide sequence in the hydrolysis of double-stranded DNA end nucleases.

According to the functional characteristics of enzymes, size and response time required cofactor, restriction enzymes can be divided into two categories, class I enzymes and enzyme II. EcoRI belongs to class II enzyme. EcoRI is a nuclease, from certain strains (EcoRI  is also the origin of its name). EcoRI is a commonly used restriction enzyme that specifically recognizes the sequence of GAATTC and cuts the DNA between G and A into fragments. The molecular weight of EcoRI is less than 105 Daltons and the reaction requires only Mg2 +. Most importantly, EcoRI  could recognize a specific cut-point in a specific base sequence, allowing the DNA molecule to undergo specific enzymatic cleavage after Class II enzyme cleavage. These fragments can be separated by gel electrophoresis , Identification.

Therefore, EcoRI is high-availability restriction enzyme and most commonly used in genetic engineering.