User:Ezgidemirkılıç/sandbox

There are several type of restriction enzyme and these restriction enzymes are divided into 4 types as type I, type II, type III and, type IV according to their features such as recognition sequences and cleavage sites. Type I, III and IV restriction enzymes are much less often used in DNA studies because of their lower DNA-cutting specificity. 

The restriction enzyme EcoRI recognizes the ssDNA sequence 5'-GAATTC'-3, and introduces a single-strand cut between the G&A nucleotides. This recognition site is a palindrome: the opposite strand also reads 5'-GAATTC'-3 and will be cut in the same way. Digestion with EcoRI, that's why, cuts the DNA into several fragments with identical single-stranded  TTAA-5' tails or "sticky ends" at both ends.