that cleave the phosphodiester bond
within a polynucleotide
chain, in contrast to exonucleases
, which cleave phosphodiester bonds
at the end of a polynucleotide chain. Restriction endonucleases
) cleave DNA
at specific sites, and are divided into three categories, Type I, Type II, and Type III, according to their mechanism of action. These enzymes are often used in genetic engineering
to make recombinant DNA
for introduction into bacterial, plant, or animal cells.
Restriction endonucleases (ENases) are products of bacteria, and can be used to map a piece of DNA.
- UvrABC endonuclease is a well documented endonuclease found in E.coli.