Talk:Restriction enzyme
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Under the heading "Types of restriction enzymes," the last sentence reads: "The vast majority of known restriction enzymes are of type II, and it is these that find the most use as laboratory tools." Though not explicitly illogical because the writer has not asserted any causation between the two clauses, it is implied that since the vast majority are type II, scientists have found the most uses for them. In truth, however, I think it's the fact that many applications of REs require cutting at specific nucleotide sequences that has driven many biotech. companies to search actively for more type II REs in nature. Therefore, it is an effect of their usefulness that there is a preponderance of type II REs in the literature. Just quibbling...
I also agree with the later suggestion that REs be identified more precisely as "restriction endonucleases." I doubt that there are any "restriction exonucleases," that might only cut at certain sequences found at the 5' or 3' end of DNA, but "endonuclease" is more descriptive, more precise, and I believe more commonly used in the literature, though perhaps not colloquially.
who found restriction enzymes?
Werner Arber, Daniel Nathans and Hamilton O. Smith were awarded the 1978 Nobel Prize in Medicine for the discovery of "restriction enzymes and their application to problems of molecular genetics".
http://nobelprize.org/medicine/laureates/1978/index.html
I think the proper name for these enzymes is "restriction endonuclease." It is more descriptive, and it is the term used by the suppliers of these enzymes. I think that "restriction enzyme" is a shorthand that we use just because "endonuclease" is a bulky word. I guess that when we figure out who first discovered them, we'll know what their official name is. adam
- I wrote that final sentence in "Types of restriction enzymes". I didn't mean to imply causation, and I agree that no such causation exists (I'm not sure about the causation in the opposite direction though; I suspect that there really are more type II systems out there than the other two types). Feel free to make it clearer.
- As far as the name, "restriction enzyme" is perhaps a bit informal, but common even in publications. Pubmed searches for "restriction enzyme" and "restriction endonuclease" turn up roughly the same number of matches ("restriction enzyme" actually has a slight edge). In informal communications "restriction enzyme" is much more common. If we want to be sticklers, or merely precise, we could go all the way and say "restriction endodeoxyribonuclease". Josh Cherry 23:16, 18 Aug 2004 (UTC)
[edit] Examples
Are we planning to make a catalog of examples? There are MANY restriciton endonucleases, and many of hte examples presented in the article are not special. Unless we are seeking a comprehensive reference, the examples list should be much shorter and only include an example of a 3' overhang, a 5' overhang, and a blunt cut. We might also want to include examples of the different types of restriction endonucleases (based on the physical relationship of recognition sequence and cut site). Finally, we should focus on the most famous or well studied ones (such as EcoRI). AdamRetchless 13:21, 6 Jul 2004 (UTC)
I like the examples linking bacteria with RE's --adds something tangible to the spooky game of pair base preoocupations .- more art too might add to understanding the physical constraints of cellular activity, or don't boundaries matter that much anymore ?
[edit] Type III enzymes
"Although these enzymes recognize specific DNA sequences, the sites of actual cleavage are at variable distances from these recognition sites, and can be hundreds of bases away" Correct me if I'm wrong, but although true of Type I enzymes, this statement is not true of Type III enzymes. Type II enzymes cut at a relatively short, specific distance outside of an asymmetrical recognition sequence, and require two recognition sites in opposing orientation to cut. Type I and some Type II enzymes also require two recognition sites to cut, but these need not normally be in opposing orientations.
Also, is it worth mentioning Kobayashi's theory that Type II (but not Type I or III) enzymes are primarily, genomic parasites, rather than a mechanism for blocking parasites such as viruses?--203.166.255.148 14:10, 24 November 2005 (UTC)
[edit] Merger
Endonuclease should be merged into this article. Brazucs (TALK | CONTRIBS) 17:43, 14 April 2006 (UTC)
- Oh... and I also believe this page should be moved to restriction endonuclease. Brazucs (TALK | CONTRIBS) 17:50, 14 April 2006 (UTC)
They are different technical subjects. We shoudl refrain from giving into the temptaion to merge all similar articles as this will only result in readers needign to sift frther through an article to find the specific information they are after, thus reducing overall readability adn effeciveness. In addition it tends to create enormous articles that are both unwieldy and over generalized. User:AnthonyBachler
"Endonuclease" covers other enzymes, such as DNase and RNase, which are certainly diferent from restriction enzymes - although a subtopic, I would think they deserve an exclusive article, and indeed the title 'restriction endonuclease' seems more appropriate. (Rafael) 25.april.2006
I also think this article and Endonuclease should be kept separate. There is no reason to burden the reader with extracting what he wants from extraneous information. I will remove the merge tags. -R. S. Shaw 19:31, 23 May 2006 (UTC)
- If everyone thinks these should be separate, why have they been merged? Isopropyl 04:01, 16 October 2006 (UTC)
- ?? Endonuclease and Restriction enzyme are still separate. -R. S. Shaw 04:28, 16 October 2006 (UTC)
[edit] Major Problem
The examples are all wrong, the 'recognition sequences' are muddled up. If the author does not correct these in the next 72 hours then I shall. —The preceding unsigned comment was added by 81.107.151.178 (talk • contribs) 21:32, 4 May 2006 (UTC)
- I'm sorry you haven't yet corrected the detected errors in the examples. If you don't want to do the minor amount of editing needed, perhaps you could let others know which entries have problems. -R. S. Shaw 19:39, 23 May 2006 (UTC)
[edit] Merge sticky end/blunt end?
A suggestion was made to merge sticky end/blunt end into DNA ligase. Another possibility mentioned is to merge it here. The issue is being discussed at Talk:DNA ligase. // habj 13:31, 8 October 2006 (UTC)
