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Topic: Restriction enzyme

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  Restriction enzyme - Wikipedia, the free encyclopedia
Restriction enzymes therefore are believed to be a mechanism evolved by bacteria to resist viral attack and to help in the removal of viral sequences.
Because recognition sequences and cleavage sites differ between restriction enzymes, the length and the exact sequence of a sticky-end "overhang", as well as whether it is the 5' end or the 3' end strand that overhangs, depends on which enzyme produced it.
If a restriction enzyme can be found such that it cuts only one possible allele of a section of DNA (that is, the alternate nucleotide of the SNP causes the restriction site to no longer exist within the section of DNA), this restriction enzyme can be used to genotype the sample without completely sequencing it.
en.wikipedia.org /wiki/Restriction_enzyme   (1048 words)

 Encyclopedia :: encyclopedia : Enzyme   (Site not responding. Last check: 2007-10-22)
Enzymes are essential to sustain life because most chemical reactions in biological cells would occur too slowly, or would lead to different products, without enzymes.
Enzymes are usually specific as to the reactions they catalyze and the substrates that are involved in these reactions.
Enzymes are very specific and it was suggested by Emil Fischer in 1890 that this was because the enzyme had a particular shape into which the substrate(s) fit exactly.
www.hallencyclopedia.com /Enzyme   (3500 words)

 Kids.Net.Au - Encyclopedia > Restriction enzyme   (Site not responding. Last check: 2007-10-22)
The position where the enzyme cuts the DNA is determined by a sequence of nucleotides that differs for each enzyme.
Restriction enzymes allow the splicing of DNA from one source (or species) into another.
Note that the DNA sequences recognised by these enzymes are palindromic-the sequence on one strand reads the same in the opposite direction on the complementary strand.
www.kids.net.au /encyclopedia-wiki/re/Restriction_enzyme   (119 words)

 Restriction Digestion of DNA
Restriction enzymes are expensive ($40 to $200 a vial): keep the enzymes at -20 C. Plan your digests to be small and convenient.
The one unit of enzyme activity is defined as the amount needed to digest 1 µg of a specific DNA in a 50 µl digest at the appropriate temperature (usually 37 C).
If multiple digests are to be done with the same enzyme, pool the 10X restriction buffer with a portion of the H2O, add the total amount of enzyme required to this mix and pipet this into the prepared sample containing the DNA and the balance of the H2O.
wheat.pw.usda.gov /homepage/lazo/methods/lazo/rdigest.html   (396 words)

 Support, restriction enzymes: Troubleshooting
Activity of restriction enzymes is usually determined using phage lambda DNA as a substrate.
Enzyme activity depends on the nature of the DNA substrate - linear, supercoiled or agarose-embedded, number of recognition sequences, nature of nucleotides flanking the recognition sequence.
If the restriction enzyme can not be heat-inactivated at 65°C (thermostable), phenol deproteinization and/or ethanol precipitation of the fragments after the restriction reaction should be performed.
www.fermentas.com /techinfo/re/troubleshoot.htm   (1508 words)

 Restriction Enzyme Analysis of DNA-Student Handout   (Site not responding. Last check: 2007-10-22)
A common use for restriction enzymes is to generate a "fingerprint" of a particular DNA molecule.
A restriction enzyme reaction contains the DNA to be analyzed, a restriction enzyme, and a restriction enzyme buffer mix.
A "unit" is usually defined as the amount of enzyme needed to digest 1 ug of bacterial virus lambda DNA in 1 hour in a 50 ul reaction.
biotech.biology.arizona.edu /labs/DNA_analysis_RE_student.html   (972 words)

 Restriction Enzyme Digestion of DNA: Introduction
Restriction enzymes are enzymes isolated from bacteria that recognize specific sequences in DNA and then cut the DNA to produce fragments, called restriction fragments.
Restriction enzymes play a very important role in the construction of recombinant DNA molecules, as is done in gene cloning experiments.
This activity is designed to enhance your understanding and retention by illustrating DNA structure, restriction enzyme digestion of DNA, analysis of digested DNA by agarose gel electrophoresis, and the principles involved in constructing a restriction map from primary data.
www.phschool.com /science/biology_place/biocoach/red/intro.html   (249 words)

 Restriction Enzyme Action of EcoRI
Restriction enzymes, also called restriction nucleases (EcoRI in this example), surrounds the DNA molecule at the point it seeks(sequence GAATTC).
It cuts one strand of the DNA double helix at one point and the second strand at a different, complementary point (between the G and the A base).
EcoRI, one of many restriction enzymes, is obtained from the bacteria Escherichia coli.
www.accessexcellence.org /AB/GG/restriction.html   (84 words)

 Bio 572: Restriction Endonucleases
The enzyme breaks the phosphodiester bonds between the fifth and sixth nucleotides in the recognition sequence.
Not all restriction enzymes recognize sequences that are palindromic.
Restriction enzymes that do not recognize palindromic sequences might therefore be described in some references using multiple sequences, since the top and bottom strand read differently.
escience.ws /b572/L5/L5.htm   (2369 words)

 Restriction enzyme digestion of DNA (basic method)
Suppose you are digesting a plasmid that comprises 3kb of vector and 2kb of insert.
You are using EcoRI (a common restriction enzyme) and you expect to see three bands: the linearised vector (3kb), the 5' end of the insert (0.5kb) and the 3' end of the insert (1.5kb).
Enzyme: 0.5µl of enzyme is plenty for a miniprep digestion.
www.methodbook.net /dna/restrdig.html   (1140 words)

 Restriction Enzyme Mapping
The program used will map out all the sites where the specific restriction endonuclease activity will occur on the sequence for a particular restriction enzyme.
Select the restriction enzymes you wish to include in the analysis.
If you decide to select the enzymes individually, you can choose from the list provided by clicking on the name of the enzyme with the left mouse button.
www.colorado.edu /chemistry/bioinfo/RestrictionEnzymeMapping.htm   (461 words)

 Restriction enzyme mapping
If a different enzyme is used the same will be true but the recognition sequence and hence the fragment sizes will be different.
The relative positions of these sites on a drawing is known as a restriction enzyme map.
A DNA molecule is mixed with a) restriction enzyme 1, b) restriction enzyme 2 or c) restriction enzyme 1 and 2 together and digestion is allowed to occur
www.herts.ac.uk /natsci/Bio/LotusNotes/Mapping/introduction.htm   (360 words)

 HIV & AIDS - Retroviruses... Revisited
In 1970 molecular biology made a U-turn when it was found that DNA could be synthesised from an RNA template by the action of a hitherto unknown enzyme which was given the name reverse transcriptase (RT).
The viral samples used by Temin and Baltimore were obtained, as far as is known, from bands sedimenting in sucrose gradients at a density of 1.16 gm/ml.
However, electron microscopy was apparently not used by the authors to control the level of purity of the viral samples and the absence of contamination by cellular debris.
www.virusmyth.net /aids/data/edhgsletsc.htm   (399 words)

 RE Resource
Restriction enzymes (REs) that are most useful for molecular biology applications possess two essential attributes: high sequence specificity and precision cutting.
Our Restriction Enzymes Resource is an interactive tool, designed to speed your research applications, for identifying REs and RE recognition sites.
The following sections of the Restriction Enzymes Resource contain general information relevant to all restriction enzymes, as well as functional groupings of enzymes with particular characteristics, procedures and applications for use, and enzyme-specific technical data.
www.promega.com /guides/re_guide   (212 words)

 Restriction Enzymes - Background
These new studies were, however, dependent on the discovery and use of the many enzymes that are able to modify or join existing DNA molecules, or to aid in the synthesis of new DNA molecules.
The first type of enzyme was called a "methylase" while the other was called a "restriction nuclease." These enzymatic tools were important to scientists who were gathering the tools needed to "cut and paste" DNA molecules.
These restriction enzymes generally have names that reflect their origin--The first letter of the name comes from the genus and the second two letters come from the species of the prokaryotic cell from which they were isolated.
www.accessexcellence.org /AE/AEC/CC/restriction.html   (1191 words)

 Restriction mapping   (Site not responding. Last check: 2007-10-22)
The enzyme HindIII cuts the fragment once to generate a 400 bp fragment (A) and a 100 bp fragment (B).
The restriction enzyme(s) you would use to cleave the vector.
Indicate the restriction enzyme(s) you would use to cleave the vector for each cloning experiment.
sci.sdsu.edu /~smaloy/MicrobialGenetics/problems/in-vitro/RE-mapping   (628 words)

 Bio::Restriction::Enzyme - A single restriction endonuclease
For most enzymes this will be within the sequence, and will be set automatically based on the forward strand cut, but it need not be.
In case of type II enzymes which which cut symmetrically, this function can be considered to return a boolean value.
Prototype enzymes are the most commonly available and usually first enzymes discoverd that have the same recognition site.
cpan.uwinnipeg.ca /htdocs/bioperl/Bio/Restriction/Enzyme.html   (3745 words)

 Restriction Enzyme Mapping 4
Maps of restriction enzyme cleavage sites are useful in planning not only cloning projects but also in gene identification, forensics, sequencing and mutagenesis projects.
Below is a description and examples of three methods used to organize restriction enzyme location on DNA fragments.
When a fragment of DNA with an unknown restriciton map is cloned into a vector containing many flanking restriction enzyme sites, it is fairly easy to identify the location of most single cuts within the unknown portion.
bioweb.wku.edu /courses/biol350/REmaps4/Review.html   (389 words)

 REBASE - The Restriction Enzyme Database
You may search for Restriction enzymes by name, species, recognition sequence, companies that sell restriction enzymes, or by authors and citations associated with each enzyme.
Remember that restrcition enzymes are often named using Roman numerals.
The Restriction Enzyme Database, is a collection of information about restriction enzymes, methylases, the microorganisms from which they have been isolated, recognition sequences, cleavage sites, methylation specificity, the commercial availability of the enzymes, and references - both published and unpublished observations (dating back to 1952).
www.biochem.ucl.ac.uk /bsm/dbbrowser/protocol/rebasefrm.html   (211 words)

 Restriction enzyme cutting sites
This is an interface to a utility that determines the locations at which the selected enzyme is cutting the human sequence.
If so specified, alternative enzymes that cut the sequence at the same location are reported.
Alternative enzymes cutting the sequence at the same place to be:
globin.cse.psu.edu /html/rsite/rsite.html   (59 words)

 Restriction Enzyme Sources
For more information on specific restriction enzymes (incubation temperature, heat inactivation, etc.) or restriction enzyme sources (biohazard level, human health implications, etc.) please check our restriction enzyme listing, or click on the bacteria name in the table below.
Bacillus megaterium produces penicillin amidase for constructing penicillins, enzymes for modifying corticosteroids, and several amino acid dehydrogenases.
Bacillus subtilis is one of the most widely used bacteria for the production of enzymes and specialty chemicals.
www.thelabrat.com /protocols/RestrictionEnzymes.shtml   (1061 words)

 206 - Restriction Enzyme Mapping
Mapping the positions of restriction enzyme cleavage sites on a DNA molecule is an important prerequisite to cloning and DNA sequencing experiments.
In this experiment, a plasmid DNA is cleaved with different combinations of restriction enzymes.
By determining the fragment size and using agarose gel electrophoresis, the relative positions of the restriction sites can be established.
www.edvotek.com /206.html   (152 words)

 Beginning Molecular Biology Laboratory Manual
Larger volumes may be necessary for preparative digests or for chromosomal DNA digests.
Add 1 to 2 μl (3 to 20 units) enzyme and mix gently.
If the DNA is to be used for another manipulation, heat inactivate the enzyme (if it is heat labile) at 70 degrees C for 15 min, phenol/chloroform extract and ethanol precipitate, or purify on Qiagen DNA purification column (http://www.qiagen.com).
research.umbc.edu /~jwolf/m3.htm   (135 words)

 Gel Electrophoresis of DNA   (Site not responding. Last check: 2007-10-22)
Electrophoresis is a technique used in the laboratory that results in the separation of charged molecules.
In this CyberLab we are separating molecules of DNA that we got from Restriction Digestion.
You have now digested a piece of DNA with Restriction Enzymes, separated the digested fragments by Agarose Gel Electrophoresis on a gel you poured, and analyzed and documented your results.
www.life.uiuc.edu /molbio/geldigest/electro.html   (390 words)

 Restriction enzyme digest of DNA
Restriction digest of one DNA sequence with commercial endonucleases
Restriction digest of one or more DNA sequences with specific endonucleases
The list of restriction enzymes was obtained from REBASE
insilico.ehu.es /restriction   (29 words)

 Restriction Maps   (Site not responding. Last check: 2007-10-22)
Input a DNA sequence and obtain several types of graphic and textual restriction maps.
Initially a graphic map is displayed of cleavage sites for all restriction enzymes in the database.
The database of enzymes used by this program was generated from the "Prototypes" file at New England Biolabs web site (www.neb.com/rebase/rebase.files.html).
arbl.cvmbs.colostate.edu /molkit/mapper/index.html   (265 words)

 NEBcutter V2.0
This tool will take a DNA sequence and find the large, non-overlapping open reading frames using the E.coli genetic code and the sites for all Type II restriction enzymes that cut the sequence just once.
By default, only enzymes available from NEB are used, but other sets may be chosen.
The maximum size of the input file is 1 MByte, and the maximum sequence length is 300 KBases.
tools.neb.com /NEBcutter2/index.php   (133 words)

 Genetics - Restriction Enzyme Mapping   (Site not responding. Last check: 2007-10-22)
Restriction enzymes are used to cut up the DNA plasmid pBR322.
After analyzing the data, students will create a plasmid that shows where each restriction enzyme cleaves the plasmid.
Student Objective(s): Students will transfer data previously collected in a restriction enzyme lab to a chart.
www.kumc.edu /gec/lpbenne2.html   (164 words)

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