Restriction Enzymes

In the 1960s, Arber and Meselson discovered the enzymatic cleavage of invading bacteriophage DNA by bacterial restriction enzymes. A decade later, Arber, Nathans, and Smith collectively demonstrated that restriction enzymes (also known as restriction endonucleases) yield specific fragments that can be used for the manipulation of DNA. The trio were later awarded the 1978 Nobel Prize in Physiology or Medicine.

Restriction enzymes, namely the Type II category, are now widely used in molecular biology, for applications such as DNA mapping and fingerprinting, cloning, and other DNA-based analyses. Each enzyme recognizes a specific recognition site, usually a palindromic pair of 4-8 bases. Once recognized, the enzyme cleaves a double stranded break that may either form overhanging “sticky ends” or blunt ends. Restriction enzymes are named according to the genus, species, and strain of bacteria from which it was isolated. See our listing of manufactured restriction enzymes from different suppliers in our enzyme search tool. In selecting restriction enzymes, take note of the optimal reaction conditions to avoid STAR activity, in which the digestion becomes non-specific. Multiple enzymes may also be compatible in one reaction for multiple digests.