ALDH2
Encyclopedia
Aldehyde dehydrogenase 2 family (mitochondrial), also known as ALDH2, is a human gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

 found on chromosome 12.

Function

The enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 encoded by this gene belongs to the aldehyde dehydrogenase
Aldehyde dehydrogenase
Aldehyde dehydrogenases are a group of enzymes that catalyse the oxidation of aldehydes.- Function :Aldehyde dehydrogenase is a polymorphic enzyme responsible for the oxidation of aldehydes to carboxylic acids, which leave the liver and are metabolized by the body’s muscle and heart...

 family of enzymes that catalyze the chemical transformation from acetaldehyde
Acetaldehyde
Acetaldehyde is an organic chemical compound with the formula CH3CHO or MeCHO. It is one of the most important aldehydes, occurring widely in nature and being produced on a large scale industrially. Acetaldehyde occurs naturally in coffee, bread, and ripe fruit, and is produced by plants as part...

 to acetic acid
Acetic acid
Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...

. Aldehyde dehydrogenase is the second enzyme of the major oxidative pathway of alcohol metabolism.

Isoforms

Two major liver isoforms of this enzyme, cytosol
Cytosol
The cytosol or intracellular fluid is the liquid found inside cells, that is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondrion into compartments....

ic and mitochondrial
Mitochondrion
In cell biology, a mitochondrion is a membrane-enclosed organelle found in most eukaryotic cells. These organelles range from 0.5 to 1.0 micrometers in diameter...

, can be distinguished by their electrophoretic
Electrophoresis
Electrophoresis, also called cataphoresis, is the motion of dispersed particles relative to a fluid under the influence of a spatially uniform electric field. This electrokinetic phenomenon was observed for the first time in 1807 by Reuss , who noticed that the application of a constant electric...

 mobilities, kinetic properties, and subcellular localizations. This gene encodes a mitochondrial isoform, which has a low Km for acetaldehyde
Acetaldehyde
Acetaldehyde is an organic chemical compound with the formula CH3CHO or MeCHO. It is one of the most important aldehydes, occurring widely in nature and being produced on a large scale industrially. Acetaldehyde occurs naturally in coffee, bread, and ripe fruit, and is produced by plants as part...

s, and is localized in mitochondrial matrix.

Clinical significance

Most Caucasians have two major isozymes, while approximately 50% of Asians have one normal copy of the ALDH2 gene and one mutant copy that encodes an inactive mitochondrial isoenzyme. A remarkably higher frequency of acute alcohol intoxication among Asians than among Caucasians has been repeatedly shown to be related to the very much reduced activity of the mutant ALDH2-2 isoenzyme. There has been a steady increase over the past 10 years in the number of Japanese alcoholics who manage to overcome their genetically determined aversion to alcoholism from the dominant effects of an ALDH2-2 mutation. This trend demonstrates that even among those least likely to succumb to alcoholism are responding to the social pressures to drink.

An activator of ALDH2 enzymatic activity, Alda-1 (N-(1,3-benzodioxol-5-ylmethyl)-2,6-dichlorobenzamide), has been shown to reduce ischemia
Ischemia
In medicine, ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. It may also be spelled ischaemia or ischæmia...

-induced cardiac damage caused by myocardial infarction
Myocardial infarction
Myocardial infarction or acute myocardial infarction , commonly known as a heart attack, results from the interruption of blood supply to a part of the heart, causing heart cells to die...

.

See also

  • Acetaldehyde dehydrogenase
    Acetaldehyde dehydrogenase
    Acetaldehyde dehydrogenases are dehydrogenase enzymes which catalyze the conversion of acetaldehyde into acetic acid. The oxidation of acetaldehyde to acetate can be summarized as follows:...

  • Alcohol dehydrogenase
    Alcohol dehydrogenase
    Alcohol dehydrogenases are a group of dehydrogenase enzymes that occur in many organisms and facilitate the interconversion between alcohols and aldehydes or ketones with the reduction of nicotinamide adenine dinucleotide...

  • Alcohol flush reaction
    Alcohol flush reaction
    Alcohol flush reaction or Oriental Flushing Syndrome is a condition in which the face and/or body experiences flushes or blotches, due to an accumulation of acetaldehyde...


Further reading

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