Talk:Cytochrome c oxidase

message: Hello Wiki Community,
I have a few suggestions for revising this article, and would appreciate any feedback or direction you can give me in doing so!
I would like to expand two sections of the article that appear unusually brief: inhibition and histochemistry. A deeper understanding of both is vital to a larger understanding of the physiological significance of Complex IV.
With regards to the inhibition component of the article, I would like to make the following edits or changes. I would first expand upon each inhibitor mentioned in the first sentence: cyanide, azide, sulfide, and carbon monoxide, with the addition of nitric oxide. I would also like to discuss the effects of interplay of two different competitive inhibitors on COX (i.e. the reduced inhibition of cyanide ion on COX with the addition of exogenous nitric oxide at high concentrations of cyanide), and list two to three examples of the effects. The similarity of all four can also be elaborated on in a short sentence after the first (before going into each inhibitor specifically), with a focus on pH sensitivity (i.e. azide) in physiological conditions, and the effects of pH sensitivity on inhibitor binding. The biochemical relationship between inhibitor binding and oxidation with enzymatic changes can also be expanded upon, and specifically changes to the binuclear center and oxidation states of metal ions upon electron transfer can be discussed within respect to each specific inhibitor. For azide, I would also like to mention the two methods of determining azide inhibition effects on COX, in-vitro (extensively studied in the late twentieth to early twenty-first century), and in-vivo induction (more recent). Lastly, ATP inhibition of COX and the overall significance of understanding COX inhibition can be discussed.
In terms of the histochemistry of COX, I would first like to discuss the significance of a histochemical analysis of COX activity (without too much overlap from the clinical significance section), specifically focusing on the relationship of mtDNA mutations to accelerated aging and the development of age-related disorders. A brief overview of all animal models utilized in histochemical examination of COX will be listed, as well as the observations made and significance of comparison across multiple animal models. A small paragraph on common protocols and methods of histochemical analysis of COX will conclude this section.
A bibliography is listed below as well as on my user page. Many of my sources are primary literature in the form of articles. Thank you, any feedback is immensely appreciated, this is a topic of interest and I would like to learn as much as I can!
References:
# Leavesley HB, Li L, Prabhakaran K, Borowitz JL, and Isom GE (September 2007). "Interaction of cyanide and nitric oxide with cytochrome c oxidase: Implications for Acute Cyanide Toxicity". Toxicological Sciences, Oxford Journals 101 (1): 101-11. doi: 10.1093/toxsci/kfm254.
# Wilson MT, Antonini G, Malatesta F, Sarti P, and Brunori M (July 1994). "Probing the oxygen binding site of cytochrome c oxidase by cyanide". The Journal of Biological Chemistry 269 (39): 24114-9. .
# Nicholls P, Marshall DC, Cooper CE, and Wilson MT (October 2013). "Sulfide inhibition of and metabolism by cytochrome c oxidase". Biochemical Society Transactions 41 (5): 1312-6. doi:10.1042/BST20130070. .
# Hevner RF and Wong-Riley MTT (November 1989). "Brain cytochrome oxidase: Purification, antibody production, and immunohistochemical/histochemical correlations in the CNS". The Journal of Neuroscience 9 (11): 3884-98. .
# Bennett MC, Mlady GW, Kwon YH, and Rose GM (June 1996). "Chronic in vivo sodium azide infusion induces selective and stable inhibition of cytochrome c oxidase". The Journal of Neurochemistry 66(6): 2606-11. .
Soniaiyengar7 (talk) 03:48, 5 May 2016 (UTC)
thread_title: Edits

message: This sentence (as of 2/8/2007) is not accurate and probably should be rewritten. 
"Cyanide, sulfide, azide and carbon monoxide all bind to Cytochrome c Oxidase, thus inhibiting the protein from functioning which results in chemical suffocation of cells."
Cytochrome c oxididase is a ferric heme protein in the resting state. While cyanide binds tightly to ferric proteins, carbon monoxide binds tightly to ferrous heme proteins. While the
mechanism of action of CO is to suffocate people by virtue of its action on ferrous heme oxygen transport proteins (i.e. hemoglobin and myoglobin), it's not a large player at the oxidase level.
Cyanide and those agents which bind tightly to CCO cause an immediate halt of aerobic respiration, and because of the buildup of chemical intermediates, will eventually cause the cessation of aerobic and anaerobic processes.
I'm complaining because there is a constant confusion among lay people (and even scientists not familiar with the area) about the mechanism of toxicity in vivo of CO and CN-. They are not the same and people trying to make this topic easier may in fact be obscuring real facts.
====================
"There are 2 molecules water gained in the Cytochrome C oxidase catalized reaction and not only one!"
Ions are usually written with the number first, then the polarity of charge, i.e. Fe2+ or Fe3+, rather than Fe+2/+3 as is written here. Man I gotta get around to learnin LaTeX 203.129.49.176 20:21, 17 May 2006 (UTC)
thread_title: Untitled

message: "There are 2 molecules water gained in the Cytochrome C oxidase catalized reaction and not only one!"
Ions are usually written with the number first, then the polarity of charge, i.e. Fe2+ or Fe3+, rather than Fe+2/+3 as is written here. Man I gotta get around to learnin LaTeX 203.129.49.176 20:21, 17 May 2006 (UTC)
thread_title: ========

message: Perhaps I'm wrong, but I've been educated that the terminal electron acceptor is oxygen (or another inorganic molecule such as Fe3+, NO3-, etc.), and that cytochrome oxidase catalyzes this reaction (not that cytochrome oxidase IS the terminal electron acceptor). In the sense that cytochrome oxidase is the final protein in the ETC to have the electron it is the terminal acceptor, but it is merely passing it off to it's final acceptor, oxygen. Therefore, I think that calling it the terminal electron acceptor is misleading and this should be reworded.
:Good point. Cytochrome C oxidase it is the final protein which accepts electrons in the electron transfer chain, but the terminal electron acceptor (in the chemical sense) is oxygen. —The preceding unsigned comment was added by Zephyris (talk • contribs) 10:37, 12 February 2007 (UTC)
thread_title:  Terminal Electron Acceptor 

message: Concerning the following extract:
"Cyanide, sulfide, azide, and carbon monoxide[5] all bind to cytochrome c oxidase, thus competitively inhibiting the protein from functioning..."
I wanted to clarify whether Cyanide was a competitive or a non-competitive inhibitor. The source given only concerns Carbon Monoxide, and some other sources (Examples: 1, 2 and 3) call Cyanide non-competetive. 
-- Mixy1  —Preceding undated comment added 19:53, 10 January 2013 (UTC)
replies: text: I was also taught that CN- is a non-competitive COX inhibitor.  I think Mixy1's refs are sufficient to establish that, and a quick search doesn't throw up any recent research to the contrary, so I've made the change.  I played safe by also removing the phrase about preventing binding of oxygen. Pastychomper (talk) 13:12, 20 March 2018 (UTC)
thread_title:  Competitive inhibitors 

message: I am no expert in the field, but the medical and drug literature commonly refer to COX as cyclo-oxygenase, a totally different system. So, many readers might make the mistake
that this discussion of COX applies to the other system. There should be a clear statement in this article that points out the difference.  — Preceding unsigned comment added by 172.56.21.235 (talk) 08:00, 16 April 2018 (UTC)
thread_title:  They need to point out that COX also refers to Cyclo-oxygenase

message: Substituted at 12:38, 29 April 2016 (UTC)
thread_title: Assessment comment

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thread_title:  External links modified 

message: The enzyme cytochrome c oxidase ... is a large transmembrane protein complex found in bacteria, archaea, and in eukaryotes in their mitochondria.
It is the last enzyme in the respiratory electron transport chain of cells located in the membrane.
The mitochondrial membrane in eukaryotes, but some other (unspecified) membrane otherwise? "I'll take 'membranes of archaea' for 500, Alex." — MaxEnt 13:03, 22 September 2018 (UTC)
thread_title:  What membrane?