1. A restriction enzyme, restriction endonuclease, an enzyme that cleaves DNA into small fragments at or near specific recognition sites (different restriction enzyme has different restriction site) within molecules known as restriction sites.
2. Restriction enzymes are found in archaea and bacteria.
3 And in bacteria and archaea they provide a defence mechanism against invading viruses.
4. Each restriction enzyme cut at the specific site, because each restriction enzyme have specific recognition site.
