Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.1.1.1 (alcohol dehydrogenase)
9,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Little is known about factors determining individual susceptibility to the physical complications of alcohol abuse but genetically determined differences in ethanol metabolism may be important. The oxidative metabolism of alcohol is catalyzed by alcohol and aldehyde dehydrogenase. Polymorphisms have been observed at two of the five loci encoding alcohol dehydrogenase subunits: ADH2 (producing three beta subunits) and ADH3 (producing two tau subunits) and also at the locus encoding the metabolically important form of aldehyde dehydrogenase, ALDH2. We have compared ADH2, ADH3 and ALDH2 allele frequencies in patients with alcohol-related cirrhosis (n = 59) and chronic pancreatitis (n = 13) with 79 local healthy control subjects. The different alleles were detected with allele-specific oligonucleotide probes after amplification of leukocyte DNA by the polymerase chain reaction. All patients and all but one control subject were homozygous ADH2*1, encoding the beta 1 subunit. No ADH2*3 alleles were detected. All 34 patients and 39 control subjects tested were homozygous ALDH2*1 encoding the active enzyme. ADH3 allele frequencies were different in patients and control subjects. ADH3*1 frequency: control subjects, 55.1%; cirrhotic patients, 62.7%; chronic pancreatitis patients, 65.4%. The difference between the patient groups combined and the control subjects was significant (p less than 0.05; G-test of Sokal and Rohlf) if it was assumed that the allele frequency in our control population was a reasonable estimate of our local population allele frequency. These results suggest that genetically determined differences in alcohol metabolism may, in part, explain predisposition to alcohol-related end-organ damage.
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PMID:Investigation of the role of polymorphisms at the alcohol and aldehyde dehydrogenase loci in genetic predisposition to alcohol-related end-organ damage. 193 84

The liver enzymes alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), which are responsible for the oxidative metabolism of ethanol, are polymorphic in humans. An allele encoding an inactive form of the mitochondrial ALDH2 is known to reduce the likelihood of alcoholism in Japanese. We hypothesized that the polymorphisms of both ALDH and ADH modify the predisposition to development of alcoholism. Therefore, we determined the genotypes of the ADH2, ADH3, and ALDH2 loci of alcoholic and nonalcoholic Chinese men living in Taiwan, using leukocyte DNA amplified by the PCR and allele-specific oligonucleotides. The alcoholics had significantly lower frequencies of the ADH2*2, ADH3*1, and ALDH2*2 alleles than did the nonalcoholics, suggesting that genetic variation in both ADH and ALDH, by modulating the rate of metabolism of ethanol and acetaldehyde, influences drinking behavior and the risk of developing alcoholism.
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PMID:Alcohol and aldehyde dehydrogenase genotypes and alcoholism in Chinese men. 201 95

Liver alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), the principal enzymes responsible for the oxidation of ethanol, are polymorphic at the ADH2, ADH3 and ALDH2 loci in human beings. Our previous studies have shown that, compared with nonalcoholic individuals, Chinese alcoholic patients without liver disease had significantly lower frequencies of the ADH2*2 and ADH3*1 alleles, which encode high maximum velocity beta 2- and gamma 1-ADH subunits, respectively, as well as a lower frequency of the ALDH2*2 allele, which encodes an enzymatically inactive subunit. The data strongly suggest that genetic variation in both ADH and ALDH may influence drinking behavior and the risk of alcoholism developing through acetaldehyde formation. To further investigate the possible role of acetaldehyde in the pathogenesis of alcoholic liver disease, we determined the ADH and ALDH genotype frequencies in patients with alcohol-related cirrhosis (n = 27), viral hepatitis-related cirrhosis (n = 29) and gastric and duodenal ulcer without relevance to alcohol (n = 30). We developed a new restriction fragment length polymorphism method to genotype the mutant and normal ALDH2 alleles by using polymerase chain reaction-directed mutagenesis, which proved to be simpler and faster than the conventional detection methods that use hybridization with allele-specific oligonucleotide probes. We found that the frequencies of the alleles ADH2*2 (57%), ADH3*1 (78%) and ALDH2*2 (9%) in the alcoholic cirrhotic patients were significantly lower than those in the healthy controls and in the patients with cirrhosis from viral hepatitis and with gastric and duodenal ulcer.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Polymorphism of alcohol and aldehyde dehydrogenase genes and alcoholic cirrhosis in Chinese patients. 790 79

Genetic variation at two polymorphic alcohol dehydrogenase loci, ADH2 and ADH3, and at the polymorphic mitochondrial aldehyde dehydrogenase locus, ALDH2, may influence the risk of developing alcoholism by modulating the rate of elimination of ethanol and the rate of formation and elimination of acetaldehyde. Populations differ in allele frequencies at these loci. We determined the genotypes at all three of these loci in Atayal natives of Taiwan. The frequencies of ADH2*2, ADH3*1, and ALDH2*1 alleles (0.91, 0.99, and 0.95, respectively) were significantly higher among the Atayal than among a predominantly Han Chinese population from Taiwan. Among the Atayal, the group with alcohol use disorders (alcohol dependence and alcohol abuse) had a significantly lower frequency of the ADH2*2 allele (0.82) than those without alcohol use disorders (0.91). The ADH2*2 allele encodes the beta 2 subunit; isozymes containing beta 2 subunits oxidize alcohol faster in vitro than the beta 1 beta 1 isozyme encoded by ADH2*1. Thus, the simplest explanation for these data is that individuals with a beta 2 isozymes have a higher rate of ethanol oxidation, which is a deterrent to alcohol abuse and dependence in some individuals. The Atayal with alcohol use disorders also had a lower frequency of ALDH2*2 than the controls; this allele is known to be responsible for the alcohol-flush reaction among Asians, and thereby deters drinking.
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PMID:Low frequency of the ADH2*2 allele among Atayal natives of Taiwan with alcohol use disorders. 794 68

We investigated the genotype of ADH2 and ADH3 in Chinese alcoholic cirrhotics and non-alcoholics by using a polymerase chain reaction and restriction-fragment-length polymorphism. This method is non-radioactive, easy to implement with good reproducibility. In the Chinese population, the frequencies of the ADH2*1 and ADH3*2 alleles were significantly higher in the alcoholic cirrhotic patients (53%; 23%) than in the viral hepatitis cirrhotics (32%; 8%) and the gastric and/or duodenal ulcer control patients (25%; 6%). On the other hand, the gastric and/or duodenal ulcer control patients and the viral hepatitis cirrhotic patients showed similar allele frequencies for the polymorphic ADH2 and ADH3 genes. These findings suggest that the alleles ADH2*2 and ADH3*1, coding for the high-Vmax beta 2-ADH and gamma 1-ADH, respectively, may play a protective role against alcoholism in Chinese patients.
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PMID:Genotyping of alcohol dehydrogenase at the ADH2 and ADH3 loci by using a polymerase chain reaction and restriction-fragment-length polymorphism in Chinese alcoholic cirrhotics and non-alcoholics. 797 42

The alcohol-flush reaction occurs in Asians who inherit the mutant ALDH2*2 allele that produces an inactive aldehyde dehydrogenase enzyme. In these individuals, high blood acetaldehyde levels are believed to be the cause of the unpleasant symptoms that follow drinking. We measured the alcohol elimination rates and intensity of flushing in Chinese subjects in whom the alcohol dehydrogenase ADH2 and ALDH2 genotypes were determined. We also correlated ADH2, ADH3, and ALDH2 genotypes with drinking behavior in 100 Chinese men. We discovered that ADH2*2 and ADH3*1, alleles that encode the high activity forms of alcohol dehydrogenase, as well as the mutant ALDH2*2 allele were less frequent in alcoholics than in controls. The presence of ALDH2*2 was associated with slower alcohol metabolism and the most intense flushing. In those homozygous for ALDH2*1, the presence of two ADH2*2 alleles correlated with slightly faster alcohol metabolism and more intense flushing, although a great deal of variability in the latter was noted.
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PMID:Alcohol and aldehyde dehydrogenase polymorphisms and alcoholism. 851 27

Two of the three class I alcohol dehydrogenase (ADH) genes (ADH2 and ADH3) encode known functional variants that act on alcohol with different efficiencies. Variants at both these genes have been implicated in alcoholism in some populations because allele frequencies differ between alcoholics and controls. Specifically, controls have higher frequencies of the variants with higher Vmax (ADH2*2 and ADH3*1). In samples both of alcoholics and of controls from three Taiwanese populations (Chinese, Ami, and Atayal) we found significant pairwise disequilibrium for all comparisons of the two functional polymorphisms and a third, presumably neutral, intronic polymorphism in ADH2. The class I ADH genes all lie within 80 kb on chromosome 4; thus, variants are not inherited independently, and haplotypes must be analyzed when evaluating the risk of alcoholism. In the Taiwanese Chinese we found that, only among those chromosomes containing the ADH3*1 variant (high Vmax), the proportions of chromosomes with ADH2*1 (low Vmax) and those with ADH2*2 (high Vmax) are significantly different between alcoholics and controls (P<10-5). The proportions of chromosomes with ADH3*1 and those with ADH3*2 are not significantly different between alcoholics and controls, on a constant ADH2 background (with ADH2*1, P=.83; with ADH2*2, P=.53). Thus, the observed differences in the frequency of the functional polymorphism at ADH3, between alcoholics and controls, can be accounted for by the disequilibrium with ADH2 in this population.
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PMID:Linkage disequilibrium at the ADH2 and ADH3 loci and risk of alcoholism. 1245 80

The genes that encode the major enzymes of alcohol metabolism, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), exhibit functional polymorphism. The variant alleles ADH2*2 and ADH3*1, which encode high-activity ADH isoforms, and the ALDH2*2 allele, which encodes the low-activity form of ALDH2, protect against alcoholism in East Asians. To investigate possible interactions among these protective genes, we genotyped 340 alcoholic and 545 control Han Chinese living in Taiwan at the ADH2, ADH3, and ALDH2 loci. After the influence of ALDH2*2 was controlled for, multiple logistic regression analysis indicated that allelic variation at ADH3 exerts no significant effect on the risk of alcoholism. This can be accounted for by linkage disequlibrium between ADH3*1 and ADH2*2 ALDH2*2 homozygosity, regardless of the ADH2 genotypes, was fully protective against alcoholism; no individual showing such homozygosity was found among the alcoholics. Logistic regression analyses of the remaining six combinatorial genotypes of the polymorphic ADH2 and ALDH2 loci indicated that individuals carrying one or two copies of ADH2*2 and a single copy of ALDH2*2 had the lowest risk (ORs 0.04-0.05) for alcoholism, as compared with the ADH2*1/*1 and ALDH2*1/*1 genotype. The disease risk associated with the ADH2*2/*2-ALDH2*1/*1 genotype appeared to be about half of that associated with the ADH2*1/*2-ALDH2*1/*1 genotype. The results suggest that protection afforded by the ADH2*2 allele may be independent of that afforded by ALDH2*2.
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PMID:Interaction between the functional polymorphisms of the alcohol-metabolism genes in protection against alcoholism. 1044 88

Polymorphism at the ADH2 and ADH3 loci of alcohol dehydrogenase (ADH) has been shown to have an effect on the predisposition to alcoholism in Asian individuals. However, the results are not conclusive for white individuals. We have analyzed the ADH genotype of 876 white individuals from Spain (n = 251), France (n = 160), Germany (n = 184), Sweden (n = 88), and Poland (n = 193). Peripheral blood samples from healthy controls and groups of patients with viral cirrhosis and alcohol-induced cirrhosis, as well as alcoholics with no liver disease, were collected on filter paper. Genotyping of the ADH2 and ADH3 loci was performed using polymerase chain reaction-restriction fragment length polymorphism methods on white cell DNA. In healthy controls, ADH2*2 frequencies ranged from 0% (France) to 5.4% (Spain), whereas ADH3*1 frequencies ranged from 47. 6% (Germany) to 62.5% (Sweden). Statistically significant differences were not found, however, between controls from different countries, nor between patients with alcoholism and/or liver disease. When all individuals were grouped in nonalcoholics (n = 451) and alcoholics (n = 425), ADH2*2 frequency was higher in nonalcoholics (3.8%) than in alcoholics (1.3%) (P =.0016), whereas the ADH3 alleles did not show differences. Linkage disequilibrium was found between ADH2 and ADH3, resulting in an association of the alleles ADH2*2 and ADH3*1, both coding for the most active enzymatic forms. In conclusion, the ADH2*2 allele decreases the risk for alcoholism, whereas the ADH2*2 and ADH3*1 alleles are found to be associated in the European population.
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PMID:Genetic polymorphism of alcohol dehydrogenase in europeans: the ADH2*2 allele decreases the risk for alcoholism and is associated with ADH3*1. 1073 56

Squamous cell carcinoma of the head and neck (SCCHN), including the oral cavity, pharynx and larynx, is an excellent tumor model to evaluate gene-environment interactions, including alcohol and alcohol-metabolizing enzymes such as alcohol dehydrogenase (ADH). We conducted a hospital-based case-control study including 182 cases with newly diagnosed SCCHN and 202 controls with non-neoplastic conditions of the head and neck that required surgery. The joint effects of lifetime alcohol use and the presence of the ADH3 'rapid' allele (ADH3(*)1) was evaluated in relation to the risk of SCCHN. Logistic regression was used to estimate the interaction between alcohol use and ADH3 genotype with adjustment for tobacco use, age, sex and race. The interaction was evaluated on both the multiplicative and additive scales. The risk of SCCHN was increased nearly 6-fold with consumption of 40 or more alcoholic beverages per week [odds ratio (OR) = 5.9; 95% confidence interval (CI) = 2.0-17.7; adjusted for age, sex, race and years of tobacco use]. We did not find any increase in risk for ADH3*1 homozygotes (OR = 0.9; CI = 0.4-1.9) or heterozygotes (OR = 0.8; CI = 0.4-1.7) relative to ADH3(*)2 homozygotes. There was no suggestion of an interaction between any alcohol use variable and the ADH3(*)1 genotype. For example, the interaction term, including the continuous variable average number of drinks per week and the ADH3 genotypes, was non-significant (P = 0.22). The study does not indicate an important role for the ADH3 (*)1 polymorphism in SCCHN, but larger numbers are needed to more precisely estimate the interaction, if any, with ADH3.
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PMID:Risk of head and neck cancer and the alcohol dehydrogenase 3 genotype. 1115 41


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