The homing endonucleases are a special type of restriction enzymes encoded by introns or inteins.
They act on the cellular DNA of the cell that synthesizes them; to be precise, in the opposite allele of the gene that encode them.
[1] The list includes some of the most studied examples.
The following concepts have been detailed: *: Nicking endonuclease: These enzymes cut only one DNA strand, leaving the other strand untouched.
**: Unknown cutting site: Researchers have not been able to determine the exact cutting site of these enzymes yet.