Copyright © Philip M. Parker, INSEAD. Terms of Use.
| Domain | Definition |
Health | An enzyme that catalyzes reversibly the final step of alcoholic fermentation by reducing an aldehyde to an alcohol. In the case of ethanol, acetaldehyde is reduced to ethanol in the presence of NADH and hydrogen. The enzyme is a zinc protein which acts on primary and secondary alcohols or hemiacetals. EC 1.1.1.1. (references) |
Source: compiled by the editor from various references; see credits. | |
(From Wikipedia, the free Encyclopedia)
The EC number of alcohol dehydrogenases is EC 1.1.1.1.
In humans, the enzyme is contained in the lining of the stomach and in the liver. It catalyzes the oxidation of ethanol to acetaldehyde:
Alcohol dehydrogenase also oxidizes methanol to formaldehyde, and the dangerous effects of the latter are the main reason for the toxicity of the former. The conventional treatment of methanol poisoning involves administration of ethanol: this keeps the alcohol dehydrogenase busy with ethanol, so that the methanol can be cleared out of the system before it is converted to formaldehyde. There is also now a newer drug for treating methanol poisoning: it blocks the action of alcohol dehydrogenase.
Humans have at least six slightly different alcohol dehydrogenases. All of them are dimers (consist of two polypeptides), with each dimer containing two zinc ions Zn2+. One of those ions is crucial for the operation of the enzyme: it is located at the catalytic site and holds the hydroxyl group of the alcohol in place.
The version of alcohol dehydrogenase in women is less effective than that in men, which is part of the reason that women have a lower tolerance for alcohol than men.
In yeast and many bacteria, alcohol dehydrogenase plays an important part in fermentation: pyruvate resulting from glycolysis is converted to acetaldehyde and carbon dioxide, and the acetaldehyde is then reduced to ethanol by alcohol dehydrogenase. The purpose of this latter step is the regeneration of NAD+, so that the energy generating glycolysis can continue. Humans exploit this process to produce alcoholic beverages, by letting yeast ferment various fruits or grains.
The main alcohol dehydrogenase in yeast is larger than the human one, consisting of four rather than just two subunits. It also contains zinc at its catalytic site. It is clear that the human and yeast alcohol dehydrogenases are closely related.
In insects such as the fruit fly, the alcohol dehydrogenase is smaller than in humans, does not contain a metal, and appears to be unrelated.
A third class of alcohol dehydrogenases, unrelated to the above two, are iron containing ones. They occur in bacteria, and an (apparently inactive) form has also been found in yeast.
In humans
This allows the consumption of alcoholic beverages, but its original purpose is probably the breakdown of alcohols naturally contained in foods or produced by bacteria in the digestive tract. Note that acetaldehyde is even more toxic than ethanol and is responsible for many of the hangover symptoms, but it is quickly converted to acetate and other harmless molecules. In yeast and bacteria
Insects
Iron containing
External links
Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Alcohol dehydrogenase."
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Source: compiled by the editor from various references; see credits. | |
| The following statistics estimate the number of searches per day across the major English-language search engines as identified by various trade publications. Hyperlinks lead to commercial use of the expression at Amazon.com. |
| Expression | Frequency per Day |
alcohol dehydrogenase | 19 |
| Source: compiled by the editor from various references; see credits. | |
| Language | Translations for "ALCOHOL DEHYDROGENASE"; alternative meanings/domain in parentheses. | ||||||||||||||||||||||
Danish | alkohol-dehydrogenase. (various references) | ||||||||||||||||||||||
Dutch | Alcoholdehydrogenase (ADHase), alcohol dehydrogenase, ADH (ADHase). (various references) | ||||||||||||||||||||||
Finnish | alkoholidehydrogenaasi. (various references) | ||||||||||||||||||||||
French | alcool deshydrogénase, alcool déshydrogénase, ADH. (various references) | ||||||||||||||||||||||
German | Alkohol-Dehydrogenase, Alkoholdehydrogenase (ADHase), ADH (ADHase, vasopressin). (various references) | ||||||||||||||||||||||
Greek | αλκοoλική αφυδρογονάση, αλκοολοδεσυδρογονάση. (various references) | ||||||||||||||||||||||
Italian | alcoldeidrogenasi (ADHase), alcol disidrogenasi, ADH (ADHase). (various references) | ||||||||||||||||||||||
Pig Latin | alcoholay ehydrogenaseday álcool desidrogenase. (various references) alcohol deshidrogenasa. (various references) alkoholdehydrogenas, NAD-oxidoreduktas. (various references) | ||||||||||||||||||||||
Copyright © Philip M. Parker, INSEAD. Terms of Use.
