Abstract
The term “restriction enzyme” is derived from the phenomenon of host-controlled restriction and modification in viral infection of bacteria, not from the ability of enzymes to recognize the specific target nucleotide sequence in the DNA and break the DNA chain. That is, the term “restriction enzyme” is not derived from the fact that the cleavage site is restricted. Bacteria initially resist infections by new bacteriophages, and this “restriction” of viral growth stems from endonucleases within the cells that destroy foreign DNA molecules from bacteriophages. Restriction enzymes are a kind of nuclease that catalyze hydrolysis of DNA strands and were discovered during investigations of the phenomenon of host-controlled restriction and modification of bacteriophages. They are not peptidases (proteases). However, it is a common mistake to use the term “restriction enzyme” for amino acid residue-specific endopeptidase such as trypsin.
