Talk:Glutathione S-transferase

This article was part of an assignment from Saint Louis University in Spring 2013 (see the course page for more details).

Comments

I had just made several hours worth of corrections on this article, and Firefox went belly-up on me (of course). Because of that, I am in no pleasant mood and will not likely be going through all that again for awhile. I will get around to fixing this article, and replacing all those beautiful external links, sometime later. Furthermore, as I have to include all the information (and around 20 times more) about GSTs in the introduction to my dissertation, I will not be entering anything under the GFDL (and/or the public domain) until I have published my dissertation and obtained a copyright on it. Sorry, but I can't put Wikipedia information in my intro and don't want to have one of my committee members read this article and accuse me of plagiarizing (myself). I'll slowly add more to the article as I find time. FMephit 18:17, 7 April 2006 (UTC)

Browsers do crash from time to time. Always better practise (as with any computer application) to save your work often (i.e. click "save page" and then click "edit this page" every fifteen minutes or so. --Seans Potato Business 22:48, 20 October 2007 (UTC)

Any movement on the thesis copyright? I'm debating whether or not I should heavily modify this article. As my dissertation was on aminotransferases, I'm not sure if I can wear an expert badge with respect to glutathione transferases, but I'm willing to give it a shot if no one else (any real experts out there?) feels like it. Pdcook (talk) 17:49, 29 September 2009 (UTC)

The article title is not optimal - as can be read in (source at end - Mannervick et al.), the trivial name is Glutathione Tranferases, (without the S-). I suggest renaming this page, and creating a auto-redirect from the current page name to the new page, however I don't have the knowledge of how to do this, and don't want to break wikipedia! Thank you! B. R. Mannervik, P. G. Board, J. Hayes, I. Listowsky and W. R. Pearson, in Gluthione Transferases and Gamma-Glutamyl Transpeptidases, Elsevier Academic Press Inc, San Diego, 2005, vol. 401, pp. 1-8. Tom Meakin (talk) 12:14, 15 January 2008 (UTC)

I agree that the article should be called glutathoine transferases (without the S-). Pdcook (talk) 17:43, 29 September 2009 (UTC)

I should be able to improve and add to this page over the next few months. I just started a research project in this area and need something to do while I run gels! Pdcook (talk) 14:56, 10 September 2009 (UTC)

Comments from Flemingrjf

• The first thing I noticed was the sign at the top of the article stating that it needs attention from an expert in Molecular and Cellular Biology. Hopefully, they are referring to you and the help they are able to provide. There is a recommended template for how articles in the molecular and cellular biology genre should be structure. You can find the article structure here [[1]].
  • That's been up since before I started this project. I'm afraid to take it down, but I'm also not sure it really applies anymore, since I've been adding to the article.
  • UPDATE: I have removed the template, in an effort to be bold. Jnims (talk) 22:11, 8 May 2013 (UTC)

• I also quickly noticed the lack of citations in the Classification paragraph. There is a considerable amount of information there, and having more than one source for this information would be optimal. If all of the information did indeed come from that one source, I would suggest finding other sources that had the same general information as this source, and citing those as well. Knowing that this information can be found in more than one source greatly helps in the validation of this information. The same can be said for the paragraph under “Nomenclature” as well.
  • I have added more sources.

• I am not sure how helpful listing the thirteen Greek names for the classes of the cytosolic GSTs is. Perhaps you could leave this alone. It just seemed a little dry and not very informational reading these Greek names. This sentence seems to contradict the sentence about human cytosolic GSTs, unless the first category of GSTs are the ones currently found in all organisms. Nonetheless, I would consider taking care of this ambiguity.
  • I have eliminated the sentence about the six human cytosolic GSTs. Other editors have said that they couldn't think of a better way to present the names, so I've left it as is, since the information is important.

• I tried changing one of the structures of the sentences, because I thought it was pretty awkwardly written. However, without the exact knowledge regarding nomenclature, I am not sure if my rewording captured what you were trying to say. Feel free to change it back.
  • Thanks.

• I also made a minor change to the wording of the last sentence in the Nomenclature paragraph to help it flow better and help with the grammar.
  • Thanks.

• I noticed that the first two paragraphs regarding the structure also came from the same source as the paragraph under “Classification.” To help prevent against plagiarism, I think it would be beneficial to read up on more sources regarding the structure and classification of these proteins.
  • I have added more sources.

• To go with the point above, the first sentence under “Structure” seemed to be a simple paraphrase of the sentence taken from the article source. The same can be said for the paragraph under “Classification” as well. It seems hard to provide one’s on voice to a protein when the information comes from only one source.
  • I had trouble finding a good, recent article about the structure of GSTs, and the one I did find seems to be the definitive source. Not much structural characterization appears to be happening, as of late. However, I have added sources.

• For example, I noticed that source number 14 provided very similar information regarding the classification and nomenclature of the two proteins. Simply listing it as another source in the beginning paragraph essentially, for me at least, doubles the validity of what is being said.
  • I have added it, thank you.

• I thought that the structure and resulting nomenclature of the different GST proteins was very hard to keep track of. Perhaps the addition of a visual, like a cladogram, would be beneficial in helping the casual reader tell the difference and relatedness between the different classes of GST proteins. The table provided was a minor help.
  • I have not been able to find an open-source image depicting the proteins, unfortunately.

• I really liked how the information from two sources was used when providing the function of the GST proteins. It helped provide a more overarching substance to the page, rather than simply a summary and rewording of one review article.
  • Thanks.

• I am not if putting when the nomenclature was developed is worth stating, but again that is your call. I would feel that unless there is particular significance to that year, then that year should be stated. Otherwise, I would leave it out. My opinion regarding this matter, however, might not be worth much.
  • I included it because many of the sources are older and it is helpful to know what is up to date.

• I liked the wording in regards to the function of GST and it having a two-fold function. However, the structure of the sentence, with the number inside the parentheses, is directly taken from the source. I would at least try to avoid this type of copying.
  • I have removed the numbers; I'm not sure how else to word the sentence.

• I really liked the first sentence on the second paragraph regarding function of the GSTs. I liked that the sentence seemed to address the overall theme of the source rather than the paraphrasing of one sentence. To me, this is how every citation should be done.
  • Thanks.

• I really enjoyed how you made the transition from their role in detoxification to their role in cell signaling in the first sentence under “Role in cell signaling.”
  • Thanks.

• The use of source 21 in providing the implications on cancer, I thought, was very well done. It seemed to capture the main point of the article in your own words.
  • Thanks.

• In regards to the section referring to the GST-tags and the assay regarding the tags, the first thing found was obviously the sign saying there were multiple issues with the section. I am not sure if citations are required for assays, but a way to include citations would be to source a paper that used the assay in their methods.
  • I added this myself, because I was hoping to attract attention from someone who knows even the slightest bit about the assays, because it is new to me.
  • UPDATE: I have deleted the template. Jnims (talk) 22:11, 8 May 2013 (UTC)

• The section also seemed to be slightly repetitive, and could be said in half of the words, I feel.
  • I have hesitated to edit this section, since I don't know anything about the assay.

• In reference to those unfamiliar with the subject, this section might be pretty hard to write for those unfamiliar with the subject. I feel that the molecular biology, such as the central dogma, and biochemistry, such as protein interactions, must be explained in order for someone with now outside knowledge to read and understand this section. So taking care of this “problem” might be hard. I highly doubt, however, that somebody with little outside knowledge would be casually reading about GST pull-down assays.
  • This is the problem I had with the section. I'm not even sure it warrants inclusion in the article, as I did not encounter it in any of the reading I did for the project, but I also don't want to remove it, in case it is important.

• In order to not drastically change this section, I have not made any changes. However, I have written what seems to me to be a paragraph that those with basic knowledge of biology can understand. I spent a reasonable amount of time in writing this, so please read it and consider it.
  • Thank you! I have used much of it, and revamped the entire section.

Here it is: “Glutathione S-transferase can be added to a protein of interest to purify it from a solution of proteins. This is done by inserting the sequence of DNA that codes for glutathione S-transferase next to the sequence of DNA that codes for the protein of interest. Thus, after transcription and translation, the glutathione S-transferase protein and the protein of interest will be fused together in what is known as a fusion protein. Logically, the glutathione S-transferase protein has strong binding affinity for glutathione and scientists can add beads that are coated with glutathione to the protein mixture. As a result, the protein of interest that is attached to the glutathione S-transferase will stick to the beads, isolating the protein from the rest of the proteins in the solution. This is known as a pull-down assay. These beads can be obtained and then washed with free glutathione to detach the protein of interest from the beads, resulting in a purified protein. A drawback of this assay is that the protein of interest is stuck to the GST.”

• I would also list the drawback to this assay in that there is the drawback that your protein of interest will have stuck to it the glutathione S transferase. If there is a technique out there that can cleave this from the protein if interest, I do not know of it.
  • I have done so, thank you.

Flemingrjf (talk) 01:39, 23 April 2013 (UTC)

• • Thank you so much! Jnims (talk) 02:01, 8 May 2013 (UTC)

zeta GSTZ1 is missing in the list of the enzymes

need adding it? -- —Preceding unsigned comment added by 24.248.198.18 (talk) 17:52, 23 December 2009 (UTC)

Please clarify "conjugation" and the sentence

Can someone who understand please clarify and change this sentence which I do not understand:

"GSTs catalyse the conjugation of reduced glutathione — via a sulfhydryl group — toelectrophilic centers on a wide variety of substrates."

Maybe there should be an article for "conjugate" (in this sense)? Nopedia (talk) 14:18, 9 January 2013 (UTC)

Comments from MChapman5

• Great leading section!
  • Thanks.
• More citations are needed in the classification and nomenclature sections. I think you use the one citation at the end to account for everything, but maybe you can just place them on several more sentences for clarification.
  • Done.
• Structure section is very well done.
  • Thanks.
• I deleted some words like "aforementioned." I think that this pulls it away from being an encyclopedic entry. The sentences stand fine on their own without it.
  • Thank you.
• I don't suppose you could find an image from a public domain article showing a pull-down or tag assay and include it in that section? It would really help to show a visualization.
  • I have had trouble finding public domain images related to GSTs in general, unfortunately.
• Are there any other uses for GST besides cancer development? What about other disease states or clinical implications? I wouldn't mind seeing a section including that information.
  • I plan to include a section about other diseases. Thanks.
  • UPDATE: I have added a Clinical significance section. Jnims (talk) 01:46, 9 May 2013 (UTC)
• Very nice job! This page looks fantastic. MChapman5 (talk) 06:34, 30 April 2013 (UTC)
  • Thank you kindly! Jnims (talk) 02:04, 8 May 2013 (UTC)

Peer Review: BreCaitlin

• In the Role in Cell Signaling section you say there are "several GST isozymes..." do you know which specific GST isozymes? Or is the next paragraph explain which specific isozyme it is? If so then never mind
  • Yes, I mentioned them in subsequent paragraphs.
• GSTs rely on GSH from synthetic enzymes are there no natural enzymes?
  • I meant that the enzymes synthesize GSH, not that they are not naturally-occurring.
• Really well organized
  • Thanks.
• Are there any other diseases associated with GSTs, like super bugs because of GSTs working with multidrug resistance protein 1?
  • Yes, I plan to add a few sentences about other diseases.
  • UPDATE: I have added a Clinical significance section. Jnims (talk) 01:45, 9 May 2013 (UTC)
• Citations look good
  • Thanks.
• Super informative, its good
  • Thank you! Jnims (talk) 18:23, 8 May 2013 (UTC)

BreCaitlin (talk) 14:17, 30 April 2013 (UTC)

Peer Review: Gpruett2

• The section on GST-tags and the GST pull-down assay needs a citation urgently.
  • I have added sources.
• You mention that GST is involved in cancer, but isn't it involved in other diseases? For instance, this article [2] mentions that it is implicated in liver disease.
  • Yes, I plan to add a few sentences about other diseases.
  • UPDATE: I have added a Clinical significance section. Jnims (talk) 01:31, 9 May 2013 (UTC)
• The structure of your article is very well organized.
  • Thanks.
• Another section you may consider adding would be a history/discovery section. This would give a little bit of background into how this family of enzymes was first discovered.
  • I am considering this, though the information about the history and discovery is quite scattered, since there are so many isozymes out there.
• Your article is super informative and I see that you have taken into account my previous suggestions.
  • I have, indeed. Thank you for your help!

Best of luck editing the rest of your article. Gpruett2 (talk) 20:55, 5 May 2013 (UTC)

• Thanks! Jnims (talk) 19:18, 8 May 2013 (UTC)

Maximus155

• How are cytosolic, mitochondrial and microsomal GSTs different. Is it simply a matter of structure?
  • Structure, sequence, and location seem to be the differences between the GSTs. Also, not all organisms have all three superfamilies.
• You say that the helix a2 has the most variability, do you mean conservation? If you do mean variability, you should clarify the statement a little.
  • I did mean variability, in that the residue that interacts with glutathione can be one of three possibilities.
• I'm a little confused about the Max All Species column in the table. Could you clarify?
  • I never understood what that was supposed to mean, so I finally deleted it.
• I believe when you talk about domains, it should be N-terminal or C-terminal instead of N-terminus or C-terminus.
  • Fixed.
• How do GSTs recognize xenobiotic substrates?
  • I will attempt to find and add this information.
  • UPDATE: I have added the following information, which I hope will suffice (I would have included more, but each enzyme class seems to have a different strategy/structure for binding nonsubstrate ligands, and I didn't find any specific information about "recognition"): "Both subunits of the GST dimer, whether hetero- or homodimeric in nature, contain a single nonsubstrate binding site, as well as a GSH-binding site. In heterodimeric GST complexes such as those formed by the cytosolic mu and alpha classes, however, the cleft between the two subunits is home to an additional high-affinity nonsubstrate xenobiotic binding site, which may account for the enzymes' ability to form heterodimers." Jnims (talk) 01:45, 9 May 2013 (UTC)
• An image of the mercapturic acid synthesis process would be nice.
  • I can't find anything in the public domain, unfortunately.
• How is glutathione involved in the signaling pathways described? Does its binding to GST affect GSTs role in signaling?
  • I believe glutathione itself is not involved in signaling, especially with GSTP, which sequesters JNK.
• Is it known how GSTP overexpression affects cancer cells? You describe its role in MAPK pathway, does it increase the levels of mitogens?
  • I don't believe it is known yet how GSTP affects cancer cells. Unfortunately, not a lot of research is being done in terms of GSTP signaling.
  • UPDATE: GSTM1 is involved with MAPK signaling prevention through sequestration of ASK1; GSTP has a similar effect on JNK signaling. However, I am still not sure exactly how the enzymes promote tumorigenesis, other than inhibiting pro-apoptotic pathways. Jnims (talk) 01:45, 9 May 2013 (UTC)
• Does the GST tag always have to be fused to the N-terminus of the protein of interest or can it be fused to the C-terminus as well?
  • The sources I've found only mentioned fusion to the N-terminus.

Well done! Good luck with everything! Maximus155 (talk) 19:26, 8 May 2013 (UTC)

• Thanks! Jnims (talk) 22:22, 8 May 2013 (UTC)

Hi -- I posted a link in the External Links section that of this page that is apparently a COI. Apologies to Wikipedia, a site I have loved for years! I wat trying to post a GST scientific "methods and protocols" handbook offered by GE Life Sciences. The handbook doesn't require registration, so I thought it was good to add the discussion. Maybe the page editors can take a look at it and decide,...if it reeks too much of promotion it can come down. http://www.gelifesciences.com/gehcls_images/GELS/Related%20Content/Files/1314807262343/litdoc18115758_20140113001413.pdf — Preceding unsigned comment added by Lv131 (talk • contribs) 21:51, 13 June 2014 (UTC)