A
protein that
cleaves a
DNA sequence at a specific point. There are 3 different kinds of Restriction Enzyme, with the most commonly used in
molecular biology being Type II. This type of restriction enzyme cleaves
pallandromic DNA sequences in double stranded DNA. For example, the
enzyme EcoRI cleaves the following sequence:
5'-GAATTC-3'
3'-CTTAAG-5'
to give two
sticky ends
5'-G AATTC-3'
3'-CTTAA G-5'
Their function in nature is to protect
bacteria from
foreign DNA by chopping it into small
fragments, which generally are not
harmful. Bacteria prevent chopping their own DNA by
methylation of self strands.
Also known as:
Restriction Endonucleases
See Also:
DNA Fingerprinting