ALDH2

Last updated
ALDH2
Available structures
PDB Ortholog search: PDBe RCSB
Identifiers
Aliases ALDH2 , ALDH-E2, ALDHI, ALDM, aldehyde dehydrogenase 2 family (mitochondrial), aldehyde dehydrogenase 2 family member
External IDs OMIM: 100650 MGI: 99600 HomoloGene: 55480 GeneCards: ALDH2
Orthologs
SpeciesHumanMouse
Entrez

217

11669

Ensembl

ENSG00000111275

ENSMUSG00000029455

UniProt

P05091

P47738

RefSeq (mRNA)

NM_001204889
NM_000690

NM_009656
NM_001308450

RefSeq (protein)

NP_000681
NP_001191818

NP_001295379
NP_033786

Location (UCSC) Chr 12: 111.77 – 111.82 Mb Chr 5: 121.7 – 121.73 Mb
PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse

Aldehyde dehydrogenase, mitochondrial is an enzyme that in humans is encoded by the ALDH2 gene located on chromosome 12. [5] [6] ALDH2 belongs to the aldehyde dehydrogenase family of enzymes. Aldehyde dehydrogenase is the second enzyme of the major oxidative pathway of alcohol metabolism. ALDH2 has a low Km for acetaldehyde, and is localized in mitochondrial matrix. The other liver isozyme, ALDH1, localizes to the cytosol. [7]

Most White people have both major isozymes, while approximately 50% of East Asians have the cytosolic isozyme but not a functional mitochondrial isozyme. A remarkably higher frequency of acute alcohol intoxication among East Asians than among Whites could be related to this absence of a catalytically active form of ALDH2. The increased exposure to acetaldehyde in individuals with the catalytically inactive form may also confer greater susceptibility to many types of cancer. [8]

Gene

The ALDH2 gene is about 44  kbp in length and contains at least 13 exons which encode 517 amino acid residues. Except for the signal NH2-terminal peptide, which is absent in the mature enzyme, the amino acid sequence deduced from the exons coincided with the reported primary structure of human liver ALDH2. Several introns contain Alu repetitive sequences. A TATA-like sequence (TTATAAAA) and a CAAT-like sequence (GTCATCAT) are located 473 and 515 bp, respectively, upstream from the translation initiation codon. [9]

Enzyme structure

The enzyme encoded by the human ALDH2 gene is a tetrameric enzyme that contains three domains; two dinucleotide-binding domains and a three-stranded beta-sheet domain. The active site of ALDH2 is divided into two halves by the nicotinamide ring of nicotinamide adenine dinucleotide (NAD+). Adjacent to the A-side (Pro-R) of the nicotinamide ring is a cluster of three cysteines (Cys301, Cys302 and Cys303) and adjacent to the B-side (Pro-S) are Thr244, Glu268, Glu476 and an ordered water molecule bound to Thr244 and Glu476. [10] Although there is a recognizable Rossmann fold, the coenzyme-binding region of ALDH2 binds NAD+ in a manner not seen in other NAD+-binding enzymes. The positions of the residues near the nicotinamide ring of NAD+ suggest a chemical mechanism whereby Glu268 functions as a general base through a bound water molecule. The sidechain amide nitrogen of Asn169 and the peptide nitrogen of Cys302 are in position to stabilize the oxyanion present in the tetrahedral transition state prior to hydride transfer. The functional importance of residue Glu487 now appears to be due to indirect interactions of this residue with the substrate-binding site via Arg264 and Arg475. [11]

Function

Mitochondrial aldehyde dehydrogenase belongs to the aldehyde dehydrogenase family of enzymes that catalyze the chemical transformation from acetaldehyde to acetic acid. Aldehyde dehydrogenase is the second enzyme of the major oxidative pathway of alcohol metabolism. Human ALDH2 is especially efficient on acetaldehyde compared to ALDH1. [12]

Ethanol metabolism in humans Ethanol metabolism.svg
Ethanol metabolism in humans

Additionally, ALDH2 functions as a protector against oxidative stress. [13]

Genetic variation

SNP: ALDH2*2
Name(s)g.42421G>A, Glu504Lys
Gene ALDH2
Chromosome 12
RegionExon
External databases
Ensembl Human SNPView
dbSNP 671
HapMap 671
SNPedia 671

The inactivating ALDH2*2 mutation is "the most common single point mutation in humans". [14] This mutation is found in very few White people, but about 50% of East Asians are heterozygous for this mutation. The ALDH2*2 allele encodes lysine instead of glutamic acid at amino acid 487, [15] distorting the NAD+ binding site. [16] [17] ALDH2 assembles and functions as a tetramer and requires all four of its components to be active in order to metabolize acetaldehyde. People heterozygous for ALDH2*2 have only 10% to 45% enzyme activity, while those homozygous for ALDH2*2 have as little as 1% to 5% remaining activity. [18]

The lack of ALDH2 activity has a number of consequences, detailed in section § Inhibition and genetic deficiency below.

Distribution

In the overall Japanese population, about 57% of individuals are homozygous for the normal allele, 40% are heterozygous for the ALDH2*2 allele, and 3% are homozygous for the ALDH2*2 allele. [15]

Clinical significance

Inhibition and genetic deficiency

Alcohol metabolism

The best-known consequence of ALDH2 dysfunction is in relation to the consumption of ethanol. People heterozygous or homozygous for the ALDH2*2 metabolize ethanol to acetaldehyde normally but metabolize acetaldehyde poorly. As a result, they accumulate increased levels of acetaldehyde after consumption of alcoholic beverages. Effects include facial flushing (i.e. the "Alcohol flush reaction"), urticaria, systemic dermatitis, and alcohol-induced respiratory reactions such as rhinitis and the exacerbation of asthma bronchoconstriction. [19] The cited allergic reaction-like symptoms: (a) do not appear due to classical IgE or T cell-related allergen-induced reactions but rather the actions of acetaldehyde in stimulating the release of histamine, a probable mediating cause of these symptoms; (b) typically occur within 30–60 minutes of ingesting alcoholic beverages; and (c) occur in other Asian as well as non-Asian individuals that are either seriously defective in metabolizing ingested ethanol past acetaldehyde to acetic acid or, alternatively, that metabolize ethanol too rapidly for ALDH2 processing. [19] [20]

People with a genetic ALDH2*2 deficiency have historically had a lower likelihood of developing alcoholism, both from stronger adverse effects and a possible reduction of dopamine release. [21] However, this effect is not absolute: during the 1980s, there has been a steady increase in the number of Japanese alcoholics who carry the ALDH2*2 mutation. A strong social pressure to drink have overcome this genetic barrier to alcoholism. [22] Disulfiram, which inhibits ALDH2 and causes a similar effect, has been used as an alcohol-quitting aid. [21]

Various conditions

More recently, ALDH2 has been implicated in a number of pathways beyond alcohol metabolism. ALDH2 dysfunction is supposedly associated with a variety of human diseases including diabetes, neurodegenerative diseases, cardiovascular diseases and stroke, cancer, Fanconi anemia, pain, osteoporosis, and the process of aging. [14] The inactivating ALDH2 rs671 polymorphism, present in up to 8% of the global population and in up to 50% of the East Asian population, is associated with increased risk of cardiovascular conditions such as coronary artery disease, alcohol-induced cardiac dysfunction, pulmonary arterial hypertension, heart failure and drug-induced cardiotoxicity. [23]

Alzheimer's disease

A case-control study in a Japanese population showed that deficiency of ALDH2 activity influences the risk for late-onset Alzheimer's disease. [13] The ALDH2 knockout mice display age-related memory deficits in various tasks, as well as endothelial dysfunction, brain atrophy, and other Alzheimer's disease-associated pathologies, including marked increases in lipid peroxidation products, amyloid-beta, p-tau and activated caspases. These behavioral and biochemical Alzheimer's disease-like deficits were efficiently ameliorated when these mice were treated with isotope-reinforced lipids (deuterated polyunsaturated fatty acids). [24]

Activation

An activator of ALDH2 enzymatic activity, Alda-1 (N-(1,3-benzodioxol-5-ylmethyl)-2,6-dichlorobenzamide), has been shown to reduce ischemia-induced cardiac damage caused by myocardial infarction. [25]

Interactions

ALDH2 has been shown to interact with GroEL. [26]

See also

Related Research Articles

A dehydrogenase is an enzyme belonging to the group of oxidoreductases that oxidizes a substrate by reducing an electron acceptor, usually NAD+/NADP+ or a flavin coenzyme such as FAD or FMN. Like all catalysts, they catalyze reverse as well as forward reactions, and in some cases this has physiological significance: for example, alcohol dehydrogenase catalyzes the oxidation of ethanol to acetaldehyde in animals, but in yeast it catalyzes the production of ethanol from acetaldehyde.

Acetaldehyde (IUPAC systematic name ethanal) is an organic chemical compound with the formula CH3 CHO, sometimes abbreviated as MeCHO. It is a colorless liquid or gas, boiling near room temperature. It is one of the most important aldehydes, occurring widely in nature and being produced on a large scale in industry. Acetaldehyde occurs naturally in coffee, bread, and ripe fruit, and is produced by plants. It is also produced by the partial oxidation of ethanol by the liver enzyme alcohol dehydrogenase and is a contributing cause of hangover after alcohol consumption. Pathways of exposure include air, water, land, or groundwater, as well as drink and smoke. Consumption of disulfiram inhibits acetaldehyde dehydrogenase, the enzyme responsible for the metabolism of acetaldehyde, thereby causing it to build up in the body.

<span class="mw-page-title-main">Alcohol dehydrogenase</span> Group of dehydrogenase enzymes

Alcohol dehydrogenases (ADH) (EC 1.1.1.1) 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 (NAD+) to NADH. In humans and many other animals, they serve to break down alcohols that are otherwise toxic, and they also participate in the generation of useful aldehyde, ketone, or alcohol groups during the biosynthesis of various metabolites. In yeast, plants, and many bacteria, some alcohol dehydrogenases catalyze the opposite reaction as part of fermentation to ensure a constant supply of NAD+.

<span class="mw-page-title-main">Acetaldehyde dehydrogenase</span> Class of enzymes

Acetaldehyde dehydrogenases are dehydrogenase enzymes which catalyze the conversion of acetaldehyde into acetyl-CoA. This can be summarized as follows:

<span class="mw-page-title-main">Alcohol flush reaction</span> Effect of alcohol consumption on the human body

Alcohol flush reaction is a condition in which a person develops flushes or blotches associated with erythema on the face, neck, shoulders, ears, and in some cases, the entire body after consuming alcoholic beverages. The reaction is the result of an accumulation of acetaldehyde, a metabolic byproduct of the catabolic metabolism of alcohol, and is caused by an aldehyde dehydrogenase 2 deficiency.

<span class="mw-page-title-main">Alcohol tolerance</span> Bodily responses to the functional effects of ethanol in alcoholic beverages

Alcohol tolerance refers to the bodily responses to the functional effects of ethanol in alcoholic beverages. This includes direct tolerance, speed of recovery from insobriety and resistance to the development of alcohol use disorder.

<span class="mw-page-title-main">Aldehyde dehydrogenase</span> Group of enzymes

Aldehyde dehydrogenases are a group of enzymes that catalyse the oxidation of aldehydes. They convert aldehydes to carboxylic acids. The oxygen comes from a water molecule. To date, nineteen ALDH genes have been identified within the human genome. These genes participate in a wide variety of biological processes including the detoxification of exogenously and endogenously generated aldehydes.

Ethanol, an alcohol found in nature and in alcoholic drinks, is metabolized through a complex catabolic metabolic pathway. In humans, several enzymes are involved in processing ethanol first into acetaldehyde and further into acetic acid and acetyl-CoA. Once acetyl-CoA is formed, it becomes a substrate for the citric acid cycle ultimately producing cellular energy and releasing water and carbon dioxide. Due to differences in enzyme presence and availability, human adults and fetuses process ethanol through different pathways. Gene variation in these enzymes can lead to variation in catalytic efficiency between individuals. The liver is the major organ that metabolizes ethanol due to its high concentration of these enzymes.

<span class="mw-page-title-main">Retinal dehydrogenase</span>

In enzymology, a retinal dehydrogenase, also known as retinaldehyde dehydrogenase (RALDH), catalyzes the chemical reaction converting retinal to retinoic acid. This enzyme belongs to the family of oxidoreductases, specifically the class acting on aldehyde or oxo- donor groups with NAD+ or NADP+ as acceptor groups, the systematic name being retinal:NAD+ oxidoreductase. This enzyme participates in retinol metabolism. The general scheme for the reaction catalyzed by this enzyme is:

<span class="mw-page-title-main">ADH1B</span> Protein-coding gene in the species Homo sapiens

Alcohol dehydrogenase 1B is an enzyme that in humans is encoded by the ADH1B gene.

<span class="mw-page-title-main">ADH1C</span> Protein-coding gene in the species Homo sapiens

Alcohol dehydrogenase 1C is an enzyme that in humans is encoded by the ADH1C gene.

<span class="mw-page-title-main">Aldehyde dehydrogenase 3 family, member A1</span> Protein-coding gene in the species Homo sapiens

Aldehyde dehydrogenase, dimeric NADP-preferring is an enzyme that in humans is encoded by the ALDH3A1 gene.

<span class="mw-page-title-main">ALDH3B2</span> Protein-coding gene in the species Homo sapiens

Aldehyde dehydrogenase family 3 member B2 is an enzyme that in humans is encoded by the ALDH3B2 gene.

<span class="mw-page-title-main">Short-term effects of alcohol consumption</span> Overview of the short-term effects of the consumption of alcoholic beverages

The short-term effects of alcohol consumption range from a decrease in anxiety and motor skills and euphoria at lower doses to intoxication (drunkenness), to stupor, unconsciousness, anterograde amnesia, and central nervous system depression at higher doses. Cell membranes are highly permeable to alcohol, so once it is in the bloodstream, it can diffuse into nearly every cell in the body.

<span class="mw-page-title-main">ALDH3B1</span> Protein-coding gene in the species Homo sapiens

Aldehyde dehydrogenase 3 family, member B1 also known as ALDH3B1 is an enzyme that in humans is encoded by the ALDH3B1 gene.

<span class="mw-page-title-main">ALDH1A1</span> Protein-coding gene in the species Homo sapiens

Aldehyde dehydrogenase 1 family, member A1, also known as ALDH1A1 or retinaldehyde dehydrogenase 1 (RALDH1), is an enzyme that is encoded by the ALDH1A1 gene.

Pseudohypoxia refers to a condition that mimics hypoxia, by having sufficient oxygen yet impaired mitochondrial respiration due to a deficiency of necessary co-enzymes, such as NAD+ and TPP. The increased cytosolic ratio of free NADH/NAD+ in cells (more NADH than NAD+) can be caused by diabetic hyperglycemia and by excessive alcohol consumption. Low levels of TPP results from thiamine deficiency.

Alcohol-induced respiratory reactions, also termed alcohol-induced asthma and alcohol-induced respiratory symptoms, are increasingly recognized as a pathological bronchoconstriction response to the consumption of alcohol that afflicts many people with a "classical" form of asthma, the airway constriction disease evoked by the inhalation of allergens. Alcohol-induced respiratory reactions reflect the operation of different and often racially related mechanisms that differ from those of classical, allergen-induced asthma.

<span class="mw-page-title-main">Alcohol intolerance</span> Medical condition

Alcohol intolerance is due to a genetic polymorphism of the aldehyde dehydrogenase enzyme, which is responsible for the metabolism of acetaldehyde. This polymorphism is most often reported in patients of East Asian descent. Alcohol intolerance may also be an associated side effect of certain drugs such as disulfiram, metronidazole, or nilutamide. Skin flushing and nasal congestion are the most common symptoms of intolerance after alcohol ingestion. It may also be characterized as intolerance causing hangover symptoms similar to the "disulfiram-like reaction" of aldehyde dehydrogenase deficiency or chronic fatigue syndrome. Severe pain after drinking alcohol may indicate a more serious underlying condition.

<span class="mw-page-title-main">Alda-1</span> Organic compound

Alda-1 is an organic compound that enhances the enzymatic activity of human ALDH2. Alda-1 has been proposed as a potential treatment for the alcohol flush reaction experienced by people with genetically deficient ALDH2.

References

  1. 1 2 3 GRCh38: Ensembl release 89: ENSG00000111275 - Ensembl, May 2017
  2. 1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000029455 - Ensembl, May 2017
  3. ↑ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ↑ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ↑ Yoshida A, Ikawa M, Hsu LC, Tani K (1985). "Molecular abnormality and cDNA cloning of human aldehyde dehydrogenases". Alcohol. 2 (1): 103–6. doi:10.1016/0741-8329(85)90024-2. PMID   4015823.
  6. ↑ Hsu LC, Tani K, Fujiyoshi T, Kurachi K, Yoshida A (Jun 1985). "Cloning of cDNAs for human aldehyde dehydrogenases 1 and 2". Proceedings of the National Academy of Sciences of the United States of America. 82 (11): 3771–5. Bibcode:1985PNAS...82.3771H. doi: 10.1073/pnas.82.11.3771 . PMC   397869 . PMID   2987944.
  7. ↑ "Entrez Gene: ALDH2 aldehyde dehydrogenase 2 family (mitochondrial)".
  8. ↑ Seitz HK, Meier P (2007). "The role of acetaldehyde in upper digestive tract cancer in alcoholics". Transl Res. 149 (6): 293–7. doi:10.1016/j.trsl.2006.12.002. PMID   17543846.
  9. ↑ Hsu LC, Bendel RE, Yoshida A (Jan 1988). "Genomic structure of the human mitochondrial aldehyde dehydrogenase gene". Genomics. 2 (1): 57–65. doi:10.1016/0888-7543(88)90109-7. PMID   2838413.
  10. ↑ González-Segura L, Ho KK, Perez-Miller S, Weiner H, Hurley TD (Feb 2013). "Catalytic contribution of threonine 244 in human ALDH2". Chemico-Biological Interactions. 202 (1–3): 32–40. Bibcode:2013CBI...202...32G. doi:10.1016/j.cbi.2012.12.009. PMC   3602351 . PMID   23295226.
  11. ↑ Steinmetz CG, Xie P, Weiner H, Hurley TD (May 1997). "Structure of mitochondrial aldehyde dehydrogenase: the genetic component of ethanol aversion". Structure. 5 (5): 701–11. doi: 10.1016/s0969-2126(97)00224-4 . PMID   9195888.
  12. ↑ Wang MF, Han CL, Yin SJ (16 March 2009). "Substrate specificity of human and yeast aldehyde dehydrogenases". Chemico-Biological Interactions. 178 (1–3): 36–9. Bibcode:2009CBI...178...36W. doi:10.1016/j.cbi.2008.10.002. PMID   18983993.
  13. 1 2 Ohta S, Ohsawa I, Kamino K, Ando F, Shimokata H (Apr 2004). "Mitochondrial ALDH2 deficiency as an oxidative stress". Annals of the New York Academy of Sciences. 1011 (1): 36–44. Bibcode:2004NYASA1011...36O. doi:10.1196/annals.1293.004. PMID   15126281. S2CID   28571902.
  14. 1 2 Chen CH, Ferreira JC, Gross ER, Mochly-Rosen D (2014). "Targeting Aldehyde Dehydrogenase 2: New Therapeutic Opportunities". Physiological Reviews. 94 (1): 1–34. doi:10.1152/physrev.00017.2013. PMC   3929114 . PMID   24382882.
  15. 1 2 Takao A, Shimoda T, Kohno S, Asai S, Harda S (May 1998). "Correlation between alcohol-induced asthma and acetaldehyde dehydrogenase-2 genotype". The Journal of Allergy and Clinical Immunology. 101 (5): 576–80. doi: 10.1016/S0091-6749(98)70162-9 . PMID   9600491.
  16. ↑ Larson HN, Weiner H, Hurley TD (August 2005). "Disruption of the coenzyme binding site and dimer interface revealed in the crystal structure of mitochondrial aldehyde dehydrogenase "Asian" variant". The Journal of Biological Chemistry. 280 (34): 30550–6. doi: 10.1074/jbc.M502345200 . PMC   1262676 . PMID   15983043.
  17. ↑ Chang HY, Mitchell A (May 2014). "Dionysian Mysteries The Aldehyde Dehydrogenase (aldh) Family". InterPro Protein Focus.
  18. ↑ Ma C, Yu B, Zhang W, Wang W, Zhang L, Zeng Q (11 September 2017). "Associations between aldehyde dehydrogenase 2 (ALDH2) rs671 genetic polymorphisms, lifestyles and hypertension risk in Chinese Han people". Scientific Reports. 7 (1): 11136. Bibcode:2017NatSR...711136M. doi:10.1038/s41598-017-11071-w. PMC   5593832 . PMID   28894224.
  19. 1 2 Adams KE, Rans TS (Dec 2013). "Adverse reactions to alcohol and alcoholic beverages". Annals of Allergy, Asthma & Immunology. 111 (6): 439–45. doi:10.1016/j.anai.2013.09.016. PMID   24267355.
  20. ↑ Linneberg A, Gonzalez-Quintela A, Vidal C, Jørgensen T, Fenger M, Hansen T, Pedersen O, Husemoen LL (Jan 2010). "Genetic determinants of both ethanol and acetaldehyde metabolism influence alcohol hypersensitivity and drinking behaviour among Scandinavians". Clinical and Experimental Allergy. 40 (1): 123–30. doi:10.1111/j.1365-2222.2009.03398.x. PMID   20205700. S2CID   40246805.
  21. 1 2 Chen CH, Ferreira JC, Gross ER, Mochly-Rosen D (2014). "Targeting Aldehyde Dehydrogenase 2: New Therapeutic Opportunities". Physiological Reviews. 94 (1): 1–34. doi:10.1152/physrev.00017.2013. PMC   3929114 . PMID   24382882.
  22. ↑ Higuchi S, Matsushita S, Imazeki H, Kinoshita T, Takagi S, Kono H (March 1994). "Aldehyde dehydrogenase genotypes in Japanese alcoholics". Lancet. 343 (8899): 741–2. doi:10.1016/S0140-6736(94)91629-2. PMID   7907720. S2CID   41404745.
  23. ↑ Zhang J, Guo Y, Zhao X, Pang J, Pan C, Wang J, Wei S, Yu X, Zhang C, Chen Y, Yin H, Xu F (2023). "The role of aldehyde dehydrogenase 2 in cardiovascular disease". Nature Reviews. Cardiology. 20 (7): 495–509. doi:10.1038/s41569-023-00839-5. PMID   36781974. S2CID   256845243.
  24. ↑ Elharram A, Czegledy NM, Golod M, Milne GL, Pollock E, Bennett BM, Shchepinov MS (December 2017). "Deuterium-reinforced polyunsaturated fatty acids improve cognition in a mouse model of sporadic Alzheimer's disease". The FEBS Journal. 284 (23): 4083–4095. doi:10.1111/febs.14291. PMC   5716852 . PMID   29024570.
  25. ↑ Chen CH, Budas GR, Churchill EN, Disatnik MH, Hurley TD, Mochly-Rosen D (Sep 2008). "Activation of aldehyde dehydrogenase-2 reduces ischemic damage to the heart". Science. 321 (5895): 1493–5. Bibcode:2008Sci...321.1493C. doi:10.1126/science.1158554. PMC   2741612 . PMID   18787169.
  26. ↑ Lee KH, Kim HS, Jeong HS, Lee YS (Oct 2002). "Chaperonin GroESL mediates the protein folding of human liver mitochondrial aldehyde dehydrogenase in Escherichia coli". Biochemical and Biophysical Research Communications. 298 (2): 216–24. doi:10.1016/S0006-291X(02)02423-3. PMID   12387818.

Further reading

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.