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Restriction enzyme


noun, plural: restriction enzymes

An enzyme that catalyzes the cleavage of DNA at restriction sites, producing small fragments used for gene splicing in recombinant DNA technology and for chromosome mapping.


These enzymes are normally produced in bacteria and archaea as a defense mechanism against foreign DNA, especially of bacteriophages. The enzymes can be classified into Types I, II and III according to their mechanism of action.

The enzymes are named after the bacteria from where they are derived, i.e. the bacterial genus, species, strain and the order of identification. For instance, Eco RI is a restriction enzyme isolated from the bacteria: Escherichia (genus) coli (species) R (RY13 strain) I (first identified).

Also called: restriction endonuclease

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User Contributions / Comments:

  • Restriction enzyme (ri STRIK shuhn EN ziem) - an enzyme that cuts double-stranded DNA into fragments by recognizing specific nucleotide sequences and cutting the DNA at those sequences.

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Souther blot and restriction mapping

Hi all, I would greatly appreciate any help with constructing a restriction map from Southern Hybridisation data. I can construct restriction ... the southern data, determine the restriction map for genomic DNA. Data: Enzyme Approximate Band Sizes E ------------- 6.0 ----- 1.8 X ------------- ...

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by Mistersnuffle
Sat Oct 04, 2014 11:17 am
Forum: Genetics
Topic: Souther blot and restriction mapping
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Views: 18

Gene Upregulation/Increased Expression in HMG-CoA Reductase

... Meaning that if you increased expression of a gene that codes for an enzyme, it would result in upregulation of that enzyme. ^What's wrong with ... G, Torres-gonzalez M, Mcgrane MM, Volek JS, Fernandez ML. Carbohydrate restriction and dietary cholesterol modulate the expression of HMG-CoA reductase ...

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by Upperninety8
Tue Sep 30, 2014 3:21 am
Forum: Genetics
Topic: Gene Upregulation/Increased Expression in HMG-CoA Reductase
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Views: 47


... of the oligo will form covalent bond with the 5'-phosphate end of the restriction enzyme-digested vector end, but the 5'-OH end of the oligo will have a nick next to the 3'-OH ...

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by kk
Fri Jul 19, 2013 12:50 pm
Forum: Molecular Biology
Replies: 9
Views: 5575

PFGE with Haemophilus influenzae

I am doing PFGE with Haemophilus influenzae. Also i am using SmaI restriction enzyme, but i can not get result. Not as smear, actually i am counting 6 bands but as we know ...

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by SMG
Sun May 05, 2013 3:07 pm
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Topic: PFGE with Haemophilus influenzae
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Restriction enzyme mapping

Is this correct? Second question. http://www.flickr.com/photos/85189286@N06/8220858932/in/photostream

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by TToe
Mon Nov 26, 2012 12:34 pm
Forum: Genetics
Topic: Restriction enzyme mapping
Replies: 1
Views: 856
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