Alcohol flushing, patch test, and ADH and ALDH genotypes in Brazilian ethnic groups.

Self reports of flushing reaction after drinking, cutaneous sensitivity to alcohol (patch test), and genotypic determination of ADH2, ADH3, and ALDH2 were studied in 53 Brazilian volunteers of different ethnic groups. Genotypes were determined using single-strand conformation polymorphism in discontinuous buffer electrophoresis. Analysis of the results indicated several cases of a reported flushing reaction among ALDH2 1/1 individuals, while all but 2 cases of ALDH2 heterozygotes reported a flushing reaction. The latter subjects also had a negative result in the patch test. These preliminary results indicate that variability in the facial flushing reaction to alcohol seems to be a phenomenon resulting not only from the presence of a deficient ALDH2*2 allele, but also from other polymorphisms of alcohol-metabolizing enzymes.

Influence of genetic variation in alcohol and aldehyde dehydrogenase on serotonin metabolism.

The influence of genetic variation in alcohol dehydrogenase (ADH; EC 1.1.1.1) and aldehyde dehydrogenase (ALDH; EC 1.2.1.3) on the metabolic pattern of serotonin (5-hydroxytryptamine, 5-HT) in humans was examined from the relative urinary concentrations of the end products 5-hydroxyindole-3-acetic acid (5-HIAA) and 5-hydroxytryptophol (5-HTOL). Healthy Caucasian (Swedish) and Oriental (Chinese) subjects were genotyped for ADH2, ADH3 and ALDH2 by a PCR/SSCP technique. The 5-HTOL/5-HIAA ratios ranged between 0.9-9.4 pmol/nmol (4.4 +/- 1.8, mean +/- SD, n = 143). No significant difference in the 5-HT metabolic pattern was observed between Caucasians and Orientals (4.3 +/- 1.8 and 4.4 +/- 1.8 pmol/nmol, respectively), nor between any of the ADH2, ADH3 and ALDH2 genotypes. Despite the modulatory effects of genetic variation of these enzymes on ethanol metabolism, the present results indicate that the individual isozyme composition of ADH2, ADH3 and ALDH2 is not important for the metabolic pattern of 5-HT.

Human gastric alcohol dehydrogenase activity: effect of age, sex, and alcoholism.

As various isoenzymes of gastric alcohol dehydrogenase exist and as the effect of sex and age on these enzymes is unknown, this study measured the activity of gastric alcohol dehydrogenase at high and low ethanol concentrations in endoscopic biopsy specimens from a total of 290 patients of various ages and from 10 patients with chronic alcoholism. Gastric alcohol dehydrogenase was also detected by immunohistological tests in biopsy specimens from 40 patients by the use of a polyclonal rabbit antibody against class I alcohol dehydrogenase. A significant correlation was found between the immunohistological reaction assessed by the intensity of the colour reaction in the biopsy specimen and the activity of alcohol dehydrogenase measured at 580 mM ethanol. While alcohol dehydrogenase activity measured at 16 mM ethanol was not significantly affected by age and sex, both factors influenced alcohol dehydrogenase activity measured at 580 mM ethanol. Young women below 50 years of age had significantly lower alcohol dehydrogenase activities in the gastric corpus and antrum when compared with age matched controls (SEM) (6.4 (0.7) v 8.8 (0.6) nmol/min/mg protein; p < 0.001 and 6.0 (1.3) v 9.5 (1.3) nmol/min/mg protein; p < 0.001). Over 50 years of age this sex difference was no longer detectable, as high Km gastric alcohol dehydrogenase activity decreases with age only in men and not in women. In addition, extremely low alcohol dehydrogenase activities have been found in gastric biopsy specimens from young male alcoholics (2.2 (0.5) nmol/min/mg protein), which returned to normal after two to three weeks of abstinence. The activity of alcohol dehydrogenase in the human stomach measured at 580 mM ethanol is decreased in young women, in elderly men, and in the subject with alcoholism. This decrease in alcohol dehydrogenase activity may contribute to the reduced first pass metabolism of ethanol associated with raised ethanol blood concentrations seen in these people.

Determination of human alcohol dehydrogenase and acetaldehyde dehydrogenase genotypes by single strand conformation polymorphism in discontinuous buffer electrophoresis.

Under appropriate conditions single strand conformation polymorphism (SSCP) analysis of polymerase chain reaction (PCR) products allows the detection of single base mutations in a given DNA fragment. We adapted this method for the routine determination of allele variants of human alcohol and acetaldehyde dehydrogenase without radioisotopic labeling. After PCR amplification of the selected exon, the DNA fragments were heat-denatured and loaded on a polyacrylamide gel containing glycerol. For electrophoresis a discontinuous buffer system was used with sulfate as leading ion and borate as trailing ion. The DNA bands were revealed by silver staining. Acrylamide concentrations, ionic strength and electrophoresis temperature were systematically investigated for each DNA fragment. The polymorphisms detected by SSCP were identical to those found by hybridization with 32P-labeled allele-specific oligonucleotides. This method avoids the use of radioactivity, is less expensive and simpler than the allele-specific oligonucleotide (ASO) methodology and thus particularly suited for routine analysis.

[Determination of alcohol dehydrogenase genotype: no correlation between isoenzyme pattern and liver cirrhosis]. / Bestimmung des Alkoholdehydrogenase-Genotyps: keine Korrelation zwischen Isoenzymmuster und Leberzirrhose.

Mounting evidence from various fields of research links the oxidation product of alcohol, acetaldehyde, with the development of alcohol abuse-related pathology. One factor governing the production of acetaldehyde is the genetically determined pattern of class I alcohol dehydrogenase isoenzymes, consisting of "fast" beta 2 and gamma 1 and "slow" beta 1 and gamma 2 subunits. Alcoholics carrying the beta 2 and gamma 1 genes might, therefore, be more susceptible to alcohol-related liver disease. To verify this hypothesis we developed a method based on the polymerase chain reaction and restriction enzyme digestion in order to genotype individuals with respect to their alcohol dehydrogenase isoenzyme pattern. In a total of 100 caucasian individuals the following genotypes were determined: beta 1 beta 1, 92; beta 1 beta 2, 8; beta 2 beta 2 0; gamma 1 gamma 1, 38; gamma 1 gamma 2, 51; gamma 2 gamma 2, 11. No statistically significant differences in the distribution of isoenzymes were detectable between alcoholics with liver disease, patients with non-alcohol abuse-related liver disease, patients with rheumatoid arthritis and healthy controls.

[Considering the psychotropic effect of alcohol]. / Gedanken zur psychotropen Wirkung von Alkohol.

The use of alcohol--one of the oldest drugs of mankind--has positive and negative effects in our societies which are related to the psychotropic actions of this substance. Alcohol exhibits an astonishingly broad spectrum of psychopharmacological effects, including anxiolytic, sedative hypnotic and stimulating euphoric components. Accordingly, alcohol affects all major neurobiological systems. Nevertheless, the psychopharmacological action varies from one individual to another. With biological markers, the recognition of differences in susceptibility to alcohol, such as a genetic predisposition to alcoholism, is attempted or indicators of abusive alcohol consumption are sought. Existing biological markers, however, are not yet specific for certain psychopharmacological actions sought by patients in a self medication process. Some possible implications of new biomedical findings for alcohol policy are discussed.

Methionine lowers circulating levels of acetaldehyde after ethanol ingestion.

Methionine, administered to ethanol treated mice and rats, significantly reduced circulating acetaldehyde levels without altering circulating levels of ethanol. Hepatic levels of acetaldehyde were also lowered by methionine. Methionine was effective when given prior to or after the administration of ethanol, but the time course of the action of methionine suggested the necessity for metabolic transformation of this amino acid in order for the acetaldehyde-lowering effect to be evidenced. Studies with humans, given methionine doses of approximately one-tenth of those used with mice, indicated that methionine can also lower acetaldehyde in humans ingesting ethanol. Given the toxic characteristics of acetaldehyde, methionine may prove effective in reducing the damaging effects of ethanol ingestion.

Degradation of aliphatic alcohols by human liver alcohol dehydrogenase: effect of ethanol and pharmacokinetic implications.

We have investigated the oxidation of low molecular weight aliphatic alcohols by Class I, II, and III alcohol dehydrogenases (ADH) isolated from human liver. These alcohols are generally present as byproducts of alcoholic beverages and referred to as alcoholic congeners. At concentrations corresponding to those in the blood after ingestion of alcoholic drinks (10-100 microM), the oxidation of propanol-1, isobutanol, 2-methylbutanol-1, and 3-methylbutanol-1 was mediated mainly by the isoenzymes of class I ADH, whereas butanol-1 was metabolized by Class I and II ADH. Class II ADH showed no activity with any of the alcohols at concentrations up to 100 microM. Lineweaver-Burk plots of the Class I ADH-catalyzed oxidation of all the congeners tested were linear in the pharmacokinetically relevant concentration range between 10 and 100 microM. Ethanol at concentrations found in the blood after moderate drinking (2.5-10 mM) caused a concentration-dependent inhibition of the congener oxidation. The experimentally determined kinetic constants were used to simulate the pharmacokinetics of propanol-1 metabolism in a multicompartment model system which accounts for first-pass elimination. The results suggest, in agreement with reported data from drinking experiments, that congener alcohols undergo considerable metabolism during the first liver passage, the extent of the first-pass metabolism depending on the ethanol dose.

Human carbonyl reductase. Nucleotide sequence analysis of a cDNA and amino acid sequence of the encoded protein.

Carbonyl reductase (EC 1.1.1.184) is one of several monomeric, NADPH-dependent oxidoreductases having wide specificity for carbonyl compounds that are generally referred to as the aldoketoreductases. The grouping of the enzyme into the family has been proposed on the basis of functional similarities and in the absence of structural data. Here, we describe the isolation and characterization of a cDNA clone complementary to human carbonyl reductase mRNA from a human placenta cDNA library constructed in phage lambda gt11. The cDNA consists of 1199 base pairs and contains an open reading frame encoding a protein comprised of 277 amino acids with a Mr of 30,375. The predicted amino acid sequence was confirmed by partial sequence analysis of the carbonyl reductase protein. Comparison of the protein sequence with the primary structures of other aldoketoreductases revealed no significant homologies. A possible homology, on the other hand, exists between carbonyl reductase and "short" subunit alcohol/polyol dehydrogenases.

cDNA sequence of the beta 2-subunit of human liver alcohol dehydrogenase.

A cDNA library of mRNA from a human liver expressing the beta 2-subunit of alcohol dehydrogenase was constructed in lambda gt11. One clone coding for 352 of a total of 374 amino acid residues of the beta 2-subunit was isolated. The sequence differed from that of the beta 1-subunit at one nucleotide position resulting in an Arg/His exchange at position 47 of the peptide chain, in agreement with data from protein sequence analysis [(1984) FEBS Lett. 173, 360-366].

Active-site-specific zinc-depleted and reconstituted cobalt(II) human-liver alcohol dehydrogenase. Preparation, characterization and complexation with NADH and trans-4-(N,N-dimethylamino)-cinnamaldehyde.

The active-site zinc atom of the beta 1 beta 1 isozyme of class I alcohol dehydrogenase (EC 1.1.1.1) from human liver was specifically removed by the chelating agent dipicolinic acid. From beta 1 gamma 1 and gamma 1 gamma 1 isozyme the active-site zinc is extracted much more slowly than from beta 1 beta 1 isozyme. Only partially active-site metal-depleted enzyme species were obtained from these isozymes. The active-site-specific reconstituted cobalt(II) derivative of the beta 1 beta 1 isozyme shows spectroscopic properties comparable to those of the active-site-specific reconstituted cobalt(II) horse liver alcohol dehydrogenase. The coenzyme-induced conformational change of the protein leads to a red shift of the d-d band from 648 nm to 673 nm. The chromophoric substrate trans-4-(N,N-dimethylamino)-cinnamaldehyde forms ternary complexes with NADH and the different isozymes, in close analogy to horse liver alcohol dehydrogenase. The differences in the active sites between beta 1 and gamma 1 subunits (threonine-48 instead of serine-48) or between zinc and cobalt(II) are reflected in the visible absorption spectra of the metal-bound chromophoric substrate.

H8Zn(c)2 and Zn(c)2Co(n)2 human liver alcohol dehydrogenase.

The zinc ion in the noncatalytic site of human beta 1 beta 1 and beta 1 gamma 1 isozymes of class I alcohol dehydrogenases (EC 1.1.1.1) was specifically replaced by Co(II) ion. The absorption and CD spectra prove that these derivatives contain cobalt bound at the noncatalytic site to the same ligands and in the same coordination geometry as in the corresponding species obtained from the horse liver EE isozyme. These Zn(c)2Co(n)2 human liver alcohol dehydrogenases could be obtained in two ways: (a) by exchange dialysis, (b) by removal of the noncatalytic zinc and subsequent insertion of cobalt(II) ion into the empty site. The human isozymes differ from the horse liver EE enzyme in the possibility of forming stable species lacking the noncatalytic zinc ion. This difference in chemical reactivity of the noncatalytic zinc atom may be related to amino acid changes in the human isozymes, compared to horse liver alcohol dehydrogenase.

Genotyping of human class I alcohol dehydrogenase. Analysis of enzymatically amplified DNA with allele-specific oligonucleotides.

Large inter-individual differences are noted in the susceptibility to alcohol-related problems. Part of this variation may be due to the different isoenzyme patterns of the alcohol-metabolizing enzymes and, consequently, different pharmacokinetics of alcohol degradation. We have used the polymerase chain reaction and oligonucleotide hybridization to amplify and analyze class I alcohol dehydrogenase isoenzyme-specific genomic DNA. The method unambiguously distinguishes between different allelic variants and thus provides a new means of elucidating the alcohol dehydrogenase isoenzyme pattern of humans.

Inactivation of carbonyl reductase from human brain by phenylglyoxal and 2,3-butanedione: a comparison with aldehyde reductase and aldose reductase.

Aldehyde reductase (alcohol:NADP+ oxidoreductase, EC 1.1.1.2), aldose reductase (alditol:NAD(P)+ 1-oxidoreductase, EC 1.1.1.21) and carbonyl reductase (secondary-alcohol:NADP+ oxidoreductase, EC 1.1.1.184) constitute the enzyme family of the aldo-keto reductases, a classification based on similar physicochemical properties and substrate specificities. The present study was undertaken in order to obtain information about the structural relationships between the three enzymes. Treatment of human aldehyde and carbonyl reductase with phenylglyoxal and 2,3-butanedione caused a complete and irreversible loss of enzyme activity, the rate of loss being proportional to the concentration of the dicarbonyl reagents. The inactivation of aldehyde reductase followed pseudo-first-order kinetics, whereas carbonyl reductase showed a more complex behavior, consistent with protein modification cooperativity. NADP+ partially prevented the loss of activity of both enzymes, and an even better protection of aldehyde reductase was afforded by the combination of coenzyme and substrate. Aldose reductase was partially inactivated by phenylglyoxal, but insensitive to 2,3-butanedione. The degree of inactivation with respect to the phenylglyoxal concentration showed saturation behavior. NADP+ partially protected the enzyme at low phenylglyoxal concentrations (0.5 mM), but showed no effect at high concentrations (5 mM). These findings suggest the presence of an essential arginine residue in the substrate-binding domain of aldehyde reductase and the coenzyme-binding site of carbonyl reductase. The effect of phenylglyoxal on aldose reductase may be explained by the modification of a reactive thiol or lysine rather than an arginine residue.

International Commission for Protection against Environmental Mutagens and Carcinogens. ICPEMC Working Paper No. 15/5. Acute aldehyde syndrome and chronic aldehydism.

Different types of alcohol dehydrogenase and of aldehyde dehydrogenase lead to different blood acetaldehyde levels. With respect to acetaldehyde levels in human blood 3 types can be distinguished: (1) the normal range, (2) the acute aldehyde syndrome, and (3) the chronic aldehydism. Acetaldehyde is electrophilic and reacts with nucleophilic groups of various macromolecules including DNA. Acetyldehyde inhibits synthetic and metabolic pathways, it interferes with the polymerization of tubulin and stimulates collagen synthesis. By depletion of cellular glutathione levels, acetaldehyde leads to lipid peroxidation and to the formation of malonaldehyde. There are indications that acetaldehyde may play a role in positively reinforcing mood changes induced by alcohol in humans.

Kinetics of carbonyl reductase from human brain.

Initial-rate analysis of the carbonyl reductase-catalysed reduction of menadione by NADPH gave families of straight lines in double-reciprocal plots consistent with a sequential mechanism being obeyed. The fluorescence of NADPH was increased up to 7-fold with a concomitant shift of the emission maximum towards lower wavelength in the presence of carbonyl reductase, and both NADPH and NADP+ caused quenching of the enzyme fluorescence, indicating formation of a binary enzyme-coenzyme complex. Deuterium isotope effects on the apparent V/Km values decreased with increasing concentrations of menadione but were independent of the NADPH concentration. The results, together with data from product inhibition studies, are consistent with carbonyl reductase obeying a compulsory-order mechanism, NADPH binding first and NADP+ leaving last. No significant differences in the kinetic properties of three molecular forms of carbonyl reductase were detectable.

Significance of alcohol dehydrogenase (ADH) as a marker of hepatic centrilobular injury: a biochemical and immunohistochemical study.

Since we demonstrated previously that alcohol dehydrogenase (ADH) is distributed predominantly in zone 3 of the hepatic acinus, we have investigated the usefulness of determinations of serum ADH activity in the assessment of hepatic injuries. The measurement of serum ADH activity appears to be useful for the detection of acute and early centrilobular hepatic damage, as deduced from the results obtained from experimental hepatic injuries produced by bromobenzene, hypoxia and acute administration of ethanol. Whereas serum ADH activity increased slightly after the generation of an acute ethanol load in rats which were given ethanol chronically, the hepatic content of ADH tended to decrease. Moreover, a rather selective reduction of hepatic ADH activity was found in zone 3 of the hepatic acinus. Thus, it is conceivable that chronic alcoholic injury to the liver may result in persistent release of ADH from hepatocytes resulting in a relatively low elevation of the level of the enzyme in the blood, rather than a sudden release of the enzyme leading to a sharp increase in the serum enzyme activity.

Human liver alcohol dehydrogenase: the unique properties of the "atypical" isoenzyme beta 2 beta 2-Bern can be explained by a single base mutation.

Two allelic variant alcohol dehydrogenase isoenzymes, beta 2 beta 2-Bern and beta 1 beta 1, coded by the ADH2 locus, were isolated from human livers of Caucasian origin. They represent the "atypical" and "typical" phenotype, respectively. beta 2 beta 2-Bern has a higher specific activity and a lower pH-optimum, has a higher kM for NAD+, is less susceptible to inactivation by iodoacetate, and cannot be activated with chloride ions. In order to define the structural basis for these properties, we determined the amino acid sequence difference between the beta 2-Bern and the beta 1 polypeptide chains. Peptides were prepared by cleavages with trypsin and CNBr, and were purified by exclusion chromatography and reverse phase high performance liquid chromatography. The structural analysis showed that beta 2-Bern differs at only one position from beta 1: Arg-47 in beta 1 is substituted for His-47 in beta 2-Bern. This exchange, which is identical to that reported for the beta 2-Oriental chain, alters the binding of the pyrophosphate group of the coenzyme NAD(H), and also that of iodoacetate, thus explaining the observed differences between beta 2 beta 2-Bern and beta 1 beta 1.