English - Turkish
Definition of restriction-enzyme in English Turkish dictionary
- restriksiyon enzim
English - English
Definition of restriction-enzyme in English English dictionary
- An endonuclease that catalyzes double-strand cleavage of DNA containing a specific sequence
- Any of a group of enzymes that catalyze the cleavage of DNA at specific sites to produce discrete fragments, used especially in genetic engineering. Also called restriction endonuclease. Protein (more specifically, an endonuclease) produced by bacteria that cleaves DNA at specific sites along its length. Thousands have been found, from many different bacteria; each recognizes a specific nucleotide sequence. In the living bacterial cell, these enzymes destroy the DNA of certain invading viruses (bacteriophages), thus placing a "restriction" on the number of viral strains that can cause infection; the bacterium's own DNA is protected from cleavage by methyl (CH3) groups, which are added by enzymes at the recognition sites to mask them. In the laboratory, restriction enzymes allow researchers to isolate DNA fragments of interest, such as those that contain genes, and to recombine them with other DNA molecules; for this reason they have become very powerful tools of recombinant DNA biotechnology (see DNA recombination)