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Er, now that I have your attention...a recent edit begs a question: how can it be possible that a sexual dichotomy exists in digestive enzyme production? I could imagine sexual dimorphism, but this article seems to assert that all women have a different gene coding for this enzyme than all men...or that some digestive enzyme genes are turned off in women, but active in men, which seems only slightly less plausible. I want to know whose theory this is.--Joel23:32, 11 July 2005 (UTC)[reply]
"It is believed that alcohol dehydrogenase in women is less effective than that in men, which can cause women to be more affected by alcohol than men."
This suggests that women have a different type of alcohol dehydrogenase. I think it would be more appropriate to state that the activity of alcohol dehydrogenase is lower.
-I agree; I believe the expression level is lower, but I don't have time to find a source, sorry! Also, shouldn't the statement about ethnic variation be re-written? It doesn't make a lot of sense as is. Are asians lower or higher in ADH? What about Jews? --Eirinn13:25, 25 October 2005 (UTC)[reply]
-its not so black and white - certain populations show polymorphisms of 2 ADH genes, so if an individual is from that population they are more likely to contain those alleles. This means they have more genes producing ADH, which leads to the problem with not being able to take alcohol as well. Asian populations tend to show higher frequencies of those genes compared to Western populations. Not sure about Jews offhand.
-Alcohol has three main different mechanisms for breakdown; P450's, ADH and peroxide, so any one pathway could be deficient in women. The ADH pathway may be perfect. Paul, 14-12-06
I got in an argument with a friend of the family once - me claiming the metabolism of alcohol provides the body no useful energy, her claiming it does. Does anyone know who is right? - GSchjetne08:52, 2 April 2006 (UTC)[reply]
Your freind is right, alcohol is a metabolic precursor to Acteyl CoA (takes a few steps to get there). This is the molecule that enters the Krebs cycle, which generates NADH for use in oxidative phosphorylation in the electron transport chain.
Aah, thanks! As a chemistry student and future engineering student I just think enthalpy... All I know about human biochemistry is it sometimes gives me a headache the day after :P --GSchjetne15:45, 22 April 2006 (UTC)[reply]
No mention has been made of elevated gene expression, in response to continuous exposure to the substrate and why this means the person has to consume progressively larger quantities to achieve the desired level of intoxication. This leads to 'stockpiling' of the enzyme and liver damage from the increased amounts of the reaction products. I don't have any sources to quote, at present. EatYerGreens13:27, 21 February 2007 (UTC)[reply]
There are two problems with methanol:
1) "Alcohol dehydrogenase is also involved in the toxicity of other types of alcohol: for instance, it oxidizes methanol to produce formaldehyde, " well in fact the formaldehyde is the toxic compound and not the methanol itself. So in this case this enzyme is not reducing the methanol toxicity, but instead it is aggravating the problems.
2) Alcohol dehydrogenase is marginarly catalisyng the methanol oxidation, its prefered substrate being ethanol. In fact only some isoenzymes are able to oxidise the methanol and even those at much lower speed compared with ethanol. The enzyme that preferes methanol to ethanol is the alcohol oxidase (1.1.3.13).
Sorry I do not have references to modify the main page.BdB-1818:36, 21 May 2007 (UTC)BdB-18[reply]
It seems a little inappropriate to say that ADH does not work well on primary alcohols, as its primary function is with the primary alcohol methanol, and one of its most toxicologically important substrates (ethylene glycol) is also primary. —Preceding unsigned comment added by Mah159 (talk • contribs) 04:10, 1 March 2008 (UTC)[reply]
"For example, populations from Europe have been found to express an allele for the alcohol dehydrogenase gene that makes it much more active than those found in populations from Asia or the Americas."
This statements are incorrect, a faster metabolizing form of ADH means a decreased risk of alcoholism (because of the production of toxic aldehydes). Many Asians have a faster metabolizing form of ADH, (but a ineffective version of the aldehydes dehydrogenase)
"If the variants of these genes encode slower metabolizing forms of ADH2 and ADH3, there is increased risk of alcoholism. The studies have found that mutations of ADH2 and ADH3 are related to alcoholism in Asian populations"
This statement is confusing, it seems to say alcoholism is a bigger problem in Asian populations, which is contrary to the facts.
ADH3 has virtually no affinity for ethanol. The active site is significantly larger than ADH1 and it binds larger substrates such as S-nitrosoglutathione. It has been linked to asthma but I am unaware of any relationship to alcohol dependence. —Preceding unsigned comment added by 150.135.59.194 (talk) 17:10, 27 October 2008 (UTC)[reply]
Unfortunately, none of the information on the particular topic of ADH ethnic variation contained in the article, nor the competing claims, contain acceptable citation. As far as Wikipedia is concerned, neither is correct and any mention of ethnic variation should be removed from the article as original research. I've tried to find mention of this in the biochem textbooks I had handy but found nothing. Right now I have no access to journals so if someone could research this and add citation it would be appreciated. Otherwise all mention of varying ADH activity among different ethnicities will be removed.71.101.95.236 (talk) 07:59, 18 June 2010 (UTC)[reply]
Would anyone be able to create or dig up a cartoon to depict the dehydrogenation mechanism? The step-by-step description is good but it would be nice if we could have an illustration. Thanks! :) Isopropyl (talk) 20:28, 27 December 2008 (UTC)[reply]
I would be happy to try and make a diagram of the activity but the step by step descripiton in the article is a little tough to follow. Any ideas about where I can look to find better information to go by? IE, electon jumping figure, location of the NAD+ etc. Adenosinetalk21:41, 30 June 2009 (UTC)[reply]
Perhaps someone could change the link to BRENDA in the "Notation" part for all enzymes. The link should be: http://www.brenda-enzymes.org/literature/lit.php4?e=1.1.1.1
The reason is that we try to establish this adress as the main one.
Best regards,
Andreas
The statement "Alcohol dehydrogenase was first discovered in the mid-1960s in Drosophila melanogaster" is not true. In the mid-1960 ADH was discovered in drosophilla though had been discovered in other organisms before this. However I am unable to find the exact date of discovery. Can anyone else help with this? —Preceding unsigned comment added by 94.192.232.151 (talk) 21:00, 30 April 2009 (UTC)[reply]
I think the following explanation for the differences among populations is essentially wrong:
The level of activity may not only be dependent on level of expression but due to allelic diversity among the population. These allelic differences have been linked to region of origin. For example, populations from Europe have been found to express an allele for the alcohol dehydrogenase gene that makes it much more active than those found in populations from Asia or the Americas.
In fact, the Alcohol Dehydrogenase (ADH) enzymatic activity of those alleles more frequent in Asian populations is not lower but higher and the overall effect may be exacerbated by a lower activity than normal in the prevalent alleles of the following enzyme in the alcohol catabolic pathway: the Aldehyde Dehydrogenase (ALDH2).
I have copied an extract from a recent scientific article on the topic to reference my previous assertion:
The metabolism of alcohol can significantly influence human drinking behaviors and the development of alcoholism (also called “alcohol dependence” [MIM %103780]), alcohol use disorder, and other alcohol-induced organ damage.1 Most ethanol digestion occurs through a two-step oxidation: alcohol to acetaldehyde and acetaldehyde to acetate. These steps are catalyzed mainly by alcohol dehydrogenase and acetaldehyde dehydrogenase 2, respectively. Various geographic regions have different frequencies for the genetic polymorphisms in the genes (ADH1B [MIM %103720], ADH1C [MIM %103730], and ALDH2 [MIM %100650]) for the primary enzymes.2–6
The protective effect against alcoholism of the ADH1B*47His (previously named “ADH2*2”) allele in East Asian populations is one of the most studied and confirmed associations of a genetic polymorphism and a complex behavior.16 In fact, three functional polymorphisms at class I ADH genes—ADH1B Arg47His and ADH1C Arg271Gln and Ile349Val—are in strong linkage disequilibrium (LD),17 and the variants ADH1B*47His and ADH1C*271Gln&349Val (previously named “ADH3*2”) produce enzymes with higher Vmax enzyme activity for alcohol oxidation. The haplotype with these three variants shows higher frequency in nonalcoholics than in alcoholics in many East Asian populations, including Han Chinese,4,7,17,18 Japanese,19,20 and Koreans,10 making it difficult to attribute the effect to any single site. In addition, the evidence that supports the protective role of ADH1B*47His is not limited to East Asian populations; it has been extended to European,21 Jewish,22 and European Australian23 populations, in which it is much less frequent than in East Asian populations. The observed protective effect of the ADH1C*349Ile allele is attributable to its strong LD with the ADH1B*47His allele in East Asian populations9,17 but appears to have an association with alcoholism in other populations in the absence of the ADH1B*47His allele.24–26
Reference: Han et al. Evidence of positive selection on a class I ADH locus. American Journal of Human Genetics (2007) vol. 80 (3) pp. 441-56
I think the line ″Humans have at least six slightly different alcohol dehydrogenases. ″ might be outdated as the RSCB's PBD-101 page on alcohol dehydrogenases says "Our bodies create at least nine different forms of alcohol dehydrogenase, each with slightly different properties.″ Here's the web address: http://pdb101.rcsb.org/motm/13
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