Definition of Restriction nuclease


Exact synonyms: Restriction Endonuclease, Restriction Enzyme
Generic synonyms: Endonuclease

Medical Definition of Restriction nuclease

1. Class of bacterial enzymes that cut DNA at specific sites. In bacteria their function is to destroy foreign DNA, such as that of bacteriophages (host DNA is specifically modified at these sites). Type I restriction endonucleases occur as a complex with the methylase and a polypeptide that binds to the recognition site on DNA. They are often not very specific and cut at a remote site. Type II restriction endonucleases are the classic experimental tools. They have very specific recognition and cutting sites. The recognition sites are short, 4-8 nucleotides and are usually palindromic sequences. Because both strands have the same sequence running in opposite directions the enzymes make double stranded breaks, which, if the site of cleavage is off centre, generates fragments with short single stranded tails, these can hybridise to the tails of other fragments and are called sticky ends. They are generally named according to the bacterium from which they were isolated (first letter of genus name and the first two letters of the specific name). The bacterial strain is identified next and multiple enzymes are given Roman numerals. For example the two enzymes isolated from the R strain of E. Coli are designated Eco RI and Eco RII. (10 Mar 1998)

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Lexicographical Neighbors of Restriction Nuclease

restricted functions
restriction-site polymorphism
restriction endonuclease
restriction enzyme
restriction enzyme cutting site
restriction enzymes
restriction fragment
restriction length polymorphism
restriction map
restriction mapping
restriction methylation
restriction nuclease (current term)
restriction site
restrictive cardiomyopathy
restrictive clause
restrictive covenant
restrictive practices
restrictive temperature

Literary usage of Restriction nuclease


1. Biotechnology in International Agricultural Research: Proceedings of the by International Rice Research Institute (1985)
"... the Tn5-carrying DNA with the restriction nuclease EcoR1 yields the complete Tn5 probe plus flanking portions of the target DNA. ..."

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