|WikiProject Molecular and Cell Biology||(Rated C-class, High-importance)|
Point of Clarification
According to my animal physiology professor, he said multiple times in lecture that while pH and CO2 levels can cause a Bohr effect, a change in temperature does not. Anybody know? Rrten00 23:34, 31 October 2006 (UTC)
Bohr originally recorded the dependence of O2 affinity on the concentration of CO2. It was later learned that the dominant process underlying his observation was the effect CO2 had on the pH of the solution. Therefore, the dominant phenomenon of the Bohr effect is dependence of O2 affinity on pH. The dependence of O2 affinity on temperature is not the Bohr effect, nor are dependencies of O2 affinity on phosphate concentration, chloride concentration, hemoglobin concentration or any number of other factors. For an excellent review of the Bohr effect, see:
The Nature and Significance of the Bohr Effect in Mammalian Hemoglobins Austen Riggs The Journal of General Physiology(43)737-52.
Since that review, work has been completed that identified amino acid side chains in at least human and lamprey hemoglobins that contribute to the Bohr effect in these proteins. There are many studies including this one
Biochemistry, 36 (22), 6663-73.
Error on diagram??
Please can someone clarify the dissociation curve diagram. The Bohr effect text in blue on the diagram surely should read "DECREASED pH". Please clarify. Thanks. Benmoor (talk) 20:52, 3 August 2008 (UTC)
Yes, you are right. The chemical equation shows that increasing CO2 forms more H+ and will decrease the pH. However Wikipedia does not allow one to edit an image as easily as editing text; it is necessary to edit and re-upload the original image file. I will leave a note at the talk pages of the editors listed in the Original update log (Aaronsharpe and Ratznium). Dirac66 (talk) 21:21, 3 August 2008 (UTC)
Acidic reaction with hemoglobin
The reactions shown are only CO2 and H2O. How about with hemoglobin, so that's: Hb + H+ → Hb.H, making hemoglobin less attractive for being bound by other oxygen 22.214.171.124 (talk) 10:24, 10 June 2012 (UTC)
The corresponding article in Russian Wikipedia states that the effect was first discovered in 1898 by the Russian physiologist Bronislav Verigo and, independently, in 1904 by Christian Bohr. The Russian article cites the 2000 Large Medical Distionary (Russian: Большой медицинский словарь) as a source, and this information appears there, indeed: link (in Russian). DmitTrix (talk) 07:56, 10 July 2013 (UTC)
Potential New Changes
Hi, I'm a student with Wiki Ed, working to improve biochemistry-linked articles. I've come up with some changes I'd like to make over the next week or two, and I thought I'd post a basic outline for what I'm hoping to do. If anyone has any questions, concerns, or feedback, feel free to let me know here or on my talk page. Thanks!
-Largely would stay the same, possibly some minor edits to improve continuity with changes in the overall structure of the article.
History and Experimental Discovery of the Bohr Effect:
-In his paper, Bohr cites several previous experiments, conducted by both him and his contemporaries, which consist of failed models and important building blocks for the eventual determination of the effect. I'll organize these successive experiments to get a timeline of the discoveries leading up to the discovery of the Bohr effect.
- There is some controversy over whether Bronislav Verigo independently discovered the effect in 1898, six years prior to Bohr. I haven't yet found any definitive proof of this, but the controversy itself should be noted.
-Include a summary of Bohr's experimental procedures and how he conclusively proved the relationship between carbon dioxide, pH, and haemoglobin oxygen affinity.
Cooperativity between Haemoglobin Subunits and Allosteric Regulation:
-Expand on current allostery section, with explanation of cooperativity in hemoglobin and its physiological effects (only cooperative effects, Bohr effect gets its own section) and elaboration on T and R states.
-A few changes to current mechanism section, mostly added emphasis on how H+ and CO2 interact with and stabilize the T-state (i.e. identify specific key residues that form salt bridges)
-This section overlaps quite a bit with the mechanism section, so I'll trim off the more mechanistic bits and add them to the other section, while focusing exclusively on physiological effects in this one.
-Evidence shows that the magnitude of the Bohr effect is inversely related to the body size of an animal, so I'd discuss this here
-Carbon monoxide, which is a competitive inhibitor (occupies oxygen binding sites on haemoglobin)
-Marine mammals (diving ability may be linked to modifications to standard Bohr effect)
Again, if you have any suggestions or concerns, just let me know.
- PEER REVIEW
- Thank you for making the Bohr Effect really comprehensible! Reading through the article, I just have some suggestions regarding organizing the sections as well as subsections to make this article flow better.
- I think it would be easier to follow if the mechanism comes right after the introduction, because the readers often want to know how it works before going further onto its application. As a result, I suggest moving the mechanism up as its own section, followed by the subsections of Allosteric interaction and T-state stabilization. The next section can be Physiological Role or Physiological Application - because now that people understand how it works, it is easier to put it into the physiological context of how it works in our body and its relationship with the body. I also suggest putting the example of marines animal right under the relationship with the body subheading because it seems to involve the same topic of body size and Bohr effect. I also made a small change in phrasing for one of your sentences :)
- Last but not least, I think you did a great job on your visual edits! Keep it up!
Peer Review 2 This article is explains the Bohr effect very clearly and is well-written. The introduction briefly introduces all the relevant physiological points that one would need to know about how different concentrations of acidic protons and CO2 affect hemoglobin's oxygen binding. The only suggestion I would make for the introduction would be to reword the phase "picking up more oxygen" because it seems a little colloquial rather than formal language. Perhaps saying something like "which results in increased oxygen binding to hemoglobin" may be a good replacement phase. The "Physiological role" section is also very well-written but only has 2 citations from the same source. One suggestion I would make would be to add more citations to this section to make it more credible. The "Mechanism" section details the R- and T-state conformations of hemoglobin but it may be a good addition to maybe describe the six coordination bonds that exist for the heme prosthetic group and how oxygen binds to each hemoglobin subunit since the first sentence of the section states the Bohr effect relies on the allosteric interactions between the hemes on hemoglobin. On a side note, it may help to mention cooperative binding of hemoglobin and how it relates to and/or is different from the Bohr effect. Overall, this is a very strong article. Great job and keep up the good work! Cmcheng28 (talk) 21:28, 22 November 2016 (UTC)