restriction endonuclease

endonuclease /en·do·nu·cle·ase/ (-noo´kle-ās) any nuclease specifically catalyzing the hydrolysis of interior bonds of ribonucleotide or deoxyribonucleotide chains.

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restriction endonuclease  an endonuclease that hydrolyzes DNA, cleaving it at an individual site of a specific base pattern.

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restriction endonuclease

[ristrik′shən en′dōno̅o̅′klē·ās]

Etymology: L, restringere + Gk, endon, within; L, nucleus, nut kernel; Fr, diastase, enzyme

an enzyme that cleaves DNA at a specific site. Each of the many endonucleases isolated from various bacteria acts at a different site, making it possible for researchers to divide DNA molecules at selected locations. See also restriction fragment length polymorphism.

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restriction endonuclease

one of over 200 enzymes isolated from bacteria that cleave any DNA molecule at specific sites which are usually palindromes of 4 to 10 or so nucleotides to yield a collection of restriction DNA fragments that can be separated, usually by electrophoresis in agarose or polyacrylamide gels, and which are highly characteristic for a particular DNA. They evolved as a defense mechanism for bacteria in that they modify the bacteria's own DNA by methylation which blocks the restriction fragmentation function but allows restriction of any foreign DNA that enters the cell. Called also restriction-modification enzyme. See also restriction map.