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Showing papers on "Aldehyde dehydrogenase published in 1995"


Journal ArticleDOI
15 May 1995-Blood
TL;DR: The ability to isolate viable cells that express high levels of cytosolic ALDH could be an important component of methodology for identifying and purifying HSC and for studying cyclophosphamide-resistant tumor cell populations.

332 citations


Journal ArticleDOI
TL;DR: The quantitative and dynamic importance of oxidative, reductive, and nonoxidative routes in the metabolism and detoxification of 4-HNE is described.

236 citations


Journal ArticleDOI
TL;DR: The sensor exhibits high sensitivity and a limit of detection in the micromolar regime (5.0 μM), as well as rapid response (60 s to reach 90% of its steady state value) and analytical determinations of aliphatic and aromatic aldehydes and consistently find that aromatic aldhydes give superior results.
Abstract: We describe the preparation, characterization, and performance of an aldehyde biosensor based on the determination of NADH generated by the enzymatic activity of immobilized (on a nylon mesh membrane) aldehyde dehydrogenase. The enzymatically generated NADH is, in turn, electrocatalytically oxidized at a glassy carbon electrode modified with an electropolymerized film of 3,4-dihydroxybenzaldehyde (3,4-DHB). We have characterized the response of the biosensor in terms of the effects of the immobilization procedure, enzyme loading, pH of the solution, and the presence of anionic species with particular emphasis on the role of phosphate anions. In addition, we have carried out studies of the kinetics of the catalytic reaction, as well as permeability studies. The sensor exhibits high sensitivity and a limit of detection in the micromolar regime (5.0 μM), as well as rapid response (60 s to reach 90% of its steady state value). We have also carried out analytical determinations of aliphatic and aromatic aldehydes and consistently find that aromatic aldehydes give superior results.

188 citations


Journal ArticleDOI
TL;DR: It was demonstrated that the aldehyde dehydrogenase gene is widespread in the Rhodococcus genus, but the components of the cytochrome P-450 system are unique to Rhoditis sp.
Abstract: Determination of the N-terminal sequences of two EPTC (S-ethyl dipropylcarbamothioate)-induced proteins from thiocarbamate-degrading Rhodococcus sp. strain NI86/21 resolved by two-dimensional electrophoresis enabled the localization of the respective structural genes on two distinct DNA fragments. One of these strongly induced proteins is a NAD(+)-dependent dehydrogenase active on aliphatic aldehydes. The second protein was identified as a cytochrome P-450 enzyme. The cytochrome P-450 gene represents the first member of a new family, CYP116. Downstream of the cytochrome P-450 gene, two genes for a [2Fe-2S] ferredoxin (rhodocoxin) and a ferredoxin reductase are located. A putative regulatory gene encoding a new member of the AraC-XylS family of positive transcriptional regulators is divergently transcribed from the cytochrome P-450 gene. By hybridization, it was demonstrated that the aldehyde dehydrogenase gene is widespread in the Rhodococcus genus, but the components of the cytochrome P-450 system are unique to Rhodococcus sp. strain NI86/21. Overexpression in Escherichia coli was achieved for all of these proteins except for the regulatory protein. Evidence for the involvement of this cytochrome P-450 system in EPTC degradation and herbicide biosafening for maize was obtained by complementation experiments using EPTC-negative Rhodococcus erythropolis SQ1 and mutant FAJ2027 as acceptor strains. N dealkylation by cytochrome P-450 and conversion of the released aldehyde into the corresponding carboxylic acid by aldehyde dehydrogenase are proposed as the reactions initiating thiocarbamate catabolism in Rhodococcus sp. strain NI86/21. In addition to the major metabolite N-depropyl EPTC, another degradation product was identified, EPTC-sulfoxide.

182 citations


Journal ArticleDOI
TL;DR: Cysteine 302 is the only strictly conserved cysteine residue among all the available sequences of the aldehyde dehydrogenase superfamily, supporting the role of this residue as the active site nucleophile of alde Hyde dehydrogenases.
Abstract: To determine the active site cysteine residue in aldehyde dehydrogenase, we mutated amino acid residues 49, 162, and 302 of recombinantly expressed rat liver mitochondrial (class 2) aldehyde dehydrogenase. The C49A and C162A mutants were fully active tetrameric enzymes, although the C162A mutant was found to be highly unstable. The C302A mutant was also a tetramer and bound coenzyme, but lacked both dehydrogenase and esterase activities. To test for the role of cysteine 302 as a nucleophile, the residue was mutated to a serine, a poor nucleophile. this C302S mutant was active but was a much poorer catalyst, with a kcat/Km value 7 x 10(5) times lower than that of the recombinant native enzyme. Unlike with native enzyme where deacylation is rate limiting, formation of the serine hemiacetal intermediate appeared to be the rate-limiting step. Cysteine 302 is the only strictly conserved cysteine residue among all the available sequences of the aldehyde dehydrogenase superfamily, supporting the role of this residue as the active site nucleophile of aldehyde dehydrogenase.

150 citations


Journal ArticleDOI
TL;DR: The results fit the proposed hypothesis for the development of alcoholism, i.e., drinking behavior is greatly influenced by the individual's gentoypes of alcohol-metabolizing enzymes, and the risk of becoming alcoholic is proportionate with the ethanol consumption of the individual.
Abstract: Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), the principal enzymes responsible for oxidative metabolism of ethanol, exist in multiple, genetically determined molecular forms. Widely different kinetic properties in some of these isozymes account for the individual differences in alcohol sensitivity. In this study we used the polymerase chain reaction/restriction fragment length polymorphism method to determine the genotypes of the ADH2 and ALDH2 loci of alcoholic and nonalcoholic Chinese living in Shanghai. We also investigated the subjects' drinking patterns by means of semistructured interviews. The alcoholics had significantly lower frequencies of the ADH22 and ALDH22 alleles than did the nonalcoholics, suggesting the inhibitory effects of these alleles for the development of alcoholism. In the nonalcoholic subjects, ADH22 had little, if any, effect, despite the significant effect of the ALDH22 allele in decreasing the alcohol consumption of the individual. Taken together, these results fit the proposed hypothesis for the development of alcoholism, i.e., drinking behavior is greatly influenced by the individual's gentoypes of alcohol-metabolizing enzymes, and the risk of becoming alcoholic is proportionate with the ethanol consumption of the individual.

150 citations


Journal ArticleDOI
TL;DR: Pre-steady state analysis showed that there was no burst of NADH formation in the dehydrogenase reaction or of p-nitrophenol formation inThe esterase reaction, implying that glutamate 268 may function as a general base necessary for the initial activation of the essential cysteine residue (302), rather than being involved in only the deacylation or hydride transfer step.
Abstract: On the basis of chemical modification studies, it was postulated that glutamate 268 was a component of the active site of liver aldehyde dehydrogenase [Abriola, D. P., Fields, R., MacKerell, A. D., Jr., & Pietruszko, R. (1987) Biochemistry 26, 5679-5684]. To study its role, the residue in human liver mitochondrial (class 2) aldehyde dehydrogenase was mutated to an aspartate, a glutamine, or a lysine, and the enzyme was expressed in Escherichia coli. The mutations did not affect the Km values for NAD or propionaldehyde, but grossly affected the catalytic activity of the enzymes when compared to recombinantly expressed native enzyme; the mutant enzymes had less that 0.4% of the specific activity of the recombinantly expressed native aldehyde dehydrogenase. The mutations also caused a long lag phase to occur prior to the steady state phase of the reaction. The activity of the mutant enzymes could not be restored by the addition of general bases such as sodium acetate, sodium formate, or imidazole. The Kd for NADH was essentially identical for the E268Q mutant and native enzyme. The three mutant forms of the enzyme possessed less than 0.8% of the esterolytic activity of the recombinantly expressed native enzyme. Pre-steady state analysis showed that there was no burst of NADH formation in the dehydrogenase reaction or of p-nitrophenol formation in the esterase reaction. This can be interpreted as implying that glutamate 268 may function as a general base necessary for the initial activation of the essential cysteine residue (302), rather than being involved in only the deacylation or hydride transfer step.(ABSTRACT TRUNCATED AT 250 WORDS)

139 citations


Journal ArticleDOI
TL;DR: Genetic polymorphisms of the ADH and ALDH genes, but not of the P450IIE1 gene, influence the risk of developing alcoholism in Japanese.
Abstract: The liver enzymes, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), which are responsible for the oxidative metabolism of ethanol, are polymorphic in humans. Cytochrome P450IIE1, an ethanol-inducible isozyme of liver microsomal P450, is also important in ethanol metabolism. Genetic polymorphisms in the 5'-flanking region of the human cytochrome P450IIE1 gene have recently been reported. We hypothesized that the polymorphisms of ADH, ALDH, and P450IIE1 modify the susceptibility to development of alcoholism. We determined the genotypes of the ADH2, ALDH2, and P450IIE1 loci of 96 Japanese alcoholics and 60 healthy male subjects, using leukocyte DNA by the restriction fragment-length polymorphism by polymerase chain reaction. The alcoholics had significantly higher frequencies of the ADH2(1) and ALDH2(1) alleles than did the healthy subjects. No significant difference in the frequency of the P450IIE1 genotype was observed between the alcoholics and the healthy subjects. In conclusion, genetic polymorphisms of the ADH and ALDH genes, but not of the P450IIE1 gene, influence the risk of developing alcoholism in Japanese.

125 citations


Journal ArticleDOI
TL;DR: The identification of an aldehyde dehydrogenase in the rat kidney that catalysed the oxidation of 9-cis- and all-trans-retinal to corresponding retinoic acids with high efficiency is reported, with 9-Cis-Retinol being 2-fold more active than all- Trans-Retinoic acid.
Abstract: The pleiotropic effects of retinoids are mediated by two families of nuclear receptors: RAR (retinoic acid receptors) and RXR (retinoid X receptors) 9-cis-Retinoic acid is a specific ligand for RXR receptors, whereas either 9-cis- or all-trans-retinoic acid activates the RAR receptor family The existence of RXRs suggests a new role for isomerization in the biology of retinoic acid We report here the identification of an aldehyde dehydrogenase in the rat kidney that catalysed the oxidation of 9-cis- and all-trans-retinal to corresponding retinoic acids with high efficiency, 9-cis-retinal being 2-fold more active than all-trans-retinal Based on several criteria, such as amino acid sequence, pH optimum, and inhibition by chloral hydrate, this enzyme was found to be a novel isoenzyme of aldehyde dehydrogenase 9-cis-Retinol, the precursor for the biosynthesis of 9-cis-retinal was identified in the rat kidney The occurrence of endogenous 9-cis-retinol and the existence of specific dehydrogenase which participates in the catalysis of 9-cis-retinal suggest that all-trans-retinoi(d) isomerization to 9-cis-retinoi(d) occurs at the retinol level, analogous to all-trans-retinol isomerization to 11-cis-retinol in the visual cycle

105 citations


Journal Article
TL;DR: In this article, the salivary content of these enzymes was found to be increased upon daily consumption of relatively large amounts of coffee or broccoli, indicating that these enzymes are abundantly present in the human diet, especially in certain vegetables and fruits.
Abstract: Human saliva was tested for the presence of cytosolic class 3 aldehyde dehydrogenase, glutathione S-transferases alpha, mu, and pi, and DT-diaphorase, enzymes that are known to catalyze the biotransformation of many xenobiotics, including some that are carcinogens and some that are antineoplastic agents. Each of these enzymes was found to be present in this fluid. Inducers of these enzymes are known to be abundantly present in the human diet, especially in certain vegetables and fruits. Further investigation revealed that the salivary content of these enzymes rapidly, coordinately, and markedly increased upon daily consumption of relatively large amounts of coffee or broccoli. The enzyme activities of interest rapidly returned to basal levels when these substances were removed from the diet. Given the important role that cytosolic class 3 aldehyde dehydrogenase, the glutathione S-transferases, and DT-diaphorase are thought to play in determining the carcinogenic potential of some cancer-producing agents as well as the cytotoxic potential of some antineoplastic agents, and assuming that their salivary levels reflect their tissue levels, quantification of the salivary content of one or more of these enzymes, a noninvasive and relatively easy undertaking, could be useful in: (a) preliminarily assessing the chemopreventive potential of various diets and drugs; (b) establishing the optimal dose and schedule in Phase I clinical trials for any putatively chemopreventive diets or drugs of interest; and (c) the rational selection and use of chemotherapeutic agents, since several are inactivated, and a few are activated, by these enzymes; alternatively, the antineoplastic agent could be selected first and then a diet that enables the agent to achieve its full therapeutic potential would be selected based on whether high or low enzyme activity would be favorable in that regard. Such measurements may also be useful as an indicator when exposure to carcinogenic/teratogenic/otherwise toxic environmental/industrial/dietary agents that induce these enzymes is suspected.

100 citations


Book ChapterDOI
TL;DR: The SDR family includes the Drosophila alcohol dehydrogenase, which has shorter subunits, no similar metal requirements, other sub-domain arrangements with different structural relationships, and other subunit interactions.
Abstract: Alcohol dehydrogenases of different types are common enzymes in nature. Two of these families, the medium-chain dehydrogenase/reductase family, MDR, and the shortchain dehydrogenase/reductase family, SDR, are well studied and known since long, but have experienced a recent “explosion” of new knowledge, extension and importance. The MDR family includes the classical zinc-containing liver alcohol dehydrogenases encompassing the classes of human liver alcohol dehydrogenase, while the SDR family includes the Drosophila alcohol dehydrogenase, which has shorter subunits, no similar metal requirements, other sub-domain arrangements with different structural relationships, and other subunit interactions.

Journal ArticleDOI
TL;DR: The ALDH2*2 allele is sufficient to cause ALDH1 deficiency in vitro and both mRNAs and immunoreactive proteins with isoelectric points ranging between those of AL DH2E and ALDH 2K were present, indicating that the subunits formed heteromers.
Abstract: Individuals heterozygous or homozygous for the variant aldehyde dehydrogenase (ALDH2) allele (ALDH2*2), which encodes a protein differing only at residue 487 from the normal protein, have decreased ALDH2 activity in liver extracts and experience cutaneous flushing when they drink alcohol. The mechanisms by which this allele exerts its dominant effect is unknown. To study this effect, the human ALDH2*1 cDNA was cloned and the ALDH2*2 allele was generated by site-directed mutagenesis. These cDNAs were transduced using retroviral vectors into HeLa and CV1 cells, which do not express ALDH2. The normal allele directed synthesis of immunoreactive ALDH2 protein (ALDH2E) with the expected isoelectric point. Extracts of these cells contained increased aldehyde dehydrogenase activity with low Km for the aldehyde substrate. The ALDH2*2 allele directed synthesis of mRNA and immunoreactive protein (ALDH2K), but the protein lacked enzymatic activity. When ALDH2*1-expressing cells were transduced with ALDH2*2 vectors, both mRNAs were expressed and immunoreactive proteins with isoelectric points ranging between those of ALDH2E and ALDH2K were present, indicating that the subunits formed heteromers. ALDH2 activity in these cells was reduced below that of the parental ALDH2*1-expressing cells. Thus, the ALDH2*2 allele is sufficient to cause ALDH2 deficiency in vitro.

Journal ArticleDOI
TL;DR: The results suggest that ADH2 and P450IIE1 gene polymorphisms may be independently associated with the development of alcoholic liver cirrhosis in Japan.

Journal ArticleDOI
TL;DR: Activity with betaine aldehyde was considerably higher than that with 4-aminobutyraldehyde, the best known substrate, and human E3 isozyme and betaineAldehyde dehydrogenase are the same enzyme.

Journal ArticleDOI
12 Dec 1995-Gene
TL;DR: Northern blot and RT-PCR-mediated analysis demonstrated that rat kidney ALDH is strongly expressed in kidney, lung, testis, intestine, stomach and trachea, but weakly in the liver.

Journal ArticleDOI
TL;DR: Results indicate that the action of daidzin differs from that proposed for the classic, broad-acting ALDH inhibitors (e.g., disulfiram), and the daidcin-sensitive mitochondrial ALDH is not the one and only enzyme that is essential for acetaldehyde metabolism in golden hamsters.
Abstract: Daidzin is a potent, selective, and reversible inhibitor of human mitochondrial aldehyde dehydrogenase (ALDH) that suppresses free-choice ethanol intake by Syrian golden hamsters. Other ALDH inhibitors, such as disulfiram (Antabuse) and calcium citrate carbimide (Temposil), have also been shown to suppress ethanol intake of laboratory animals and are thought to act by inhibiting the metabolism of acetaldehyde produced from ingested ethanol. To determine whether or not daidzin inhibits acetaldehyde metabolism in vivo, plasma acetaldehyde in daidzin-treated hamsters was measured after the administration of a test dose of ethanol. Daidzin treatment (150 mg/kg per day i.p. for 6 days) significantly suppresses (> 70%) hamster ethanol intake but does not affect overall acetaldehyde metabolism. In contrast, after administration of the same ethanol dose, plasma acetaldehyde concentration in disulfiram-treated hamsters reaches 0.9 mM, 70 times higher than that of the control. In vitro, daidzin suppresses hamster liver mitochondria-catalyzed acetaldehyde oxidation very potently with an IC50 value of 0.4 microM, which is substantially lower than the daidzin concentration (70 microM) found in the liver mitochondria of daidzin-treated hamsters. These results indicate that (i) the action of daidzin differs from that proposed for the classic, broad-acting ALDH inhibitors (e.g., disulfiram), and (ii) the daidzin-sensitive mitochondrial ALDH is not the one and only enzyme that is essential for acetaldehyde metabolism in golden hamsters.

Journal ArticleDOI
14 Apr 1995-Gene
TL;DR: It is proposed that the two sets of enzymes have arisen separately, but with the muconic acid semialdehyde dehydrogenases and the hydratases being recruited, respectively, from the same ancestral sources.


Journal ArticleDOI
TL;DR: A procedure for ALDH I2 detection consisting in a differentiation between the 'atypical' allele and the 'wild' allele has been improved through PCR and subsequent MboII digestion, which permits a rapid and non-radioactive detection of atypical AL DH I2 on a PCR product without the use of allele specific oligonucleotides.

Journal ArticleDOI
TL;DR: It is established that in addition to ALDH, GST overexpression can contribute to acquired resistance of tumor cells to 4HC and, furthermore, suggest that modulators that target the GSH/GST system could be useful in overcoming CPA resistance in the clinic.

Journal ArticleDOI
TL;DR: High-level cytosolic class-3 aldehyde dehydrogenase (ALDH-3)-mediated oxazaphosphorine-specific resistance was induced in cultured human breast adenocarcinoma MCF-7/0 cells by growing them in the presence of 30 microM catechol for 5 days and resistance was transient in that cellular sensitivity to mafosfamide was fully restored after only a few days when the inducing agent was removed from the culture medium.

Book ChapterDOI
TL;DR: The results obtained with both in vivo and in vitro inhibitors indicate that aldehyde oxidase plays a major role in homovanillic (HV) and 5-hydroxytryptamine (5-HT) metabolism in guinea pig liver.
Abstract: Publisher Summary This chapter discusses the role of aldehyde oxidase in biogenic amine metabolism. It shows that both homovanillyl aldehyde and 5-hydroxy-3-indoleacetaldehyde are substrates for guinea pig liver aldehyde oxidase. The results obtained with both in vivo and in vitro inhibitors indicate that aldehyde oxidase plays a major role in homovanillic (HV) and 5-hydroxytryptamine (5-HT) metabolism in guinea pig liver. In view of the similarity between the guinea pig and human liver aldehyde oxidase, it is likely that human hepatic aldehyde oxidase may also be important in biogenic amine metabolism. The urinary metabolites of 5-HT in have been examined in oriental subjects, but no correlation was found between 5-hydroxyindoleacetic acid (5-HIAA) production and mitochondrial aldehyde dehydrogenase genotype. It was suggested that cytosolic aldehyde dehydrogenase could oxidize physiological concentrations of 5-hydroxyindoleacetaldehyde when the mitochondrial isozyme is absent. However, this oxidation could equally well be carried out by aldehyde oxidase. Although peripheral plasma levels of HV acid—the deaminated and O-methylated metabolite of dopamine—are often used as an indicator of central dopaminergic activity. Lambert have shown that HVA is produced locally, perhaps from circulating DOPA.

Journal ArticleDOI
Mark J. Stewart1, K. Malek1, Qing Xiao1, Katrina M. Dipple1, David W. Crabb1 
TL;DR: The expression of ALDH5 mRNA in a human hepatoma is demonstrated and it is suggested that the gene product is enzymatically active and probably resides in the mitochondria.

Journal ArticleDOI
TL;DR: The present results for D-ADH, combined with data from the literature, establish that aldehyde oxidation, manifest as dismutation, is a widespread property of alcohol dehydrogenases with potential physiological importance in alcohol metabolism and alde Hyde detoxification.
Abstract: The ability of Drosophila alcohol dehydrogenase (D-ADH) to catalyze the oxidation of aldehydes to carboxylic acids has been re-examined. Prior studies are shown to have been compromised by a nonenzymic reaction between the aldehydic substrates and amine-containing buffers, e.g., glycine or Tris, and an amine-catalyzed addition of aldehyde to NAD+. These reactions interfere with spectrophotometric assays for monitoring aldehyde oxidation and obscure the nature and scope of D-ADH-catalyzed aldehyde oxidation, particularly at physiological pH. Use of nonreactive buffers, such as pyrophosphate or phosphate, and 1H NMR spectroscopy to monitor all the components of the reaction mixture reveals the facile dismutation of aldehydes into equimolar quantities of the corresponding acids and alcohols at both neutral and high pH. At high pH, dismutation is accompanied by a small burst of NADH production to a steady-state concentration ( < 10 microM) that represents a partitioning between NADH dissociation and aldehyde reduction. The increase in A340 is therefore not a direct measure of the aldehyde oxidation reaction, and the resulting kinetic values cannot be compared to those for alcohol dehydrogenation. The present results for D-ADH, combined with data from the literature, establish that aldehyde oxidation, manifest as dismutation, is a widespread property of alcohol dehydrogenases with potential physiological importance in alcohol metabolism and aldehyde detoxification.

Journal ArticleDOI
TL;DR: It is concluded that treatment with disulfiram and cyanamide affects serotonin metabolism leading to increased production of 5-hydroxytryptophol, but there is a marked inter-individual variability in degree of response.
Abstract: The effect of the aldehyde dehydrogenase inhibitors disulfiram (Antabuse®) and cyanamide (calcium carbimide, Dipsan®) on the metabolism of serotonin measured as relative amounts of the metabolites 5-hydroxyindole-3-acetic acid and 5-hydroxytryptophol in urine were studied in alcoholic patients. Sixteen out of 23 patients receiving drug therapy showed elevated excretion of 5-hydroxytryptophol. However, there was a marked, 15-fold, variability in 5-hydroxytryptophol excretion rate between patients. A high degree of variability was also seen in another group of patients studied before and after introduction of drug therapy. When patients were followed during the dose interval, a time-dependent response after each single dose could be observed. The disulfiram response lasted over the course of several days whereas the response to cyanamide lasted for less than 12 hr. It is concluded that treatment with disulfiram and cyanamide affects serotonin metabolism leading to increased production of 5-hydroxytryptophol, but there is a marked inter-individual variability in degree of response.

Journal Article
TL;DR: PEITC inhibits liver ALDH with a potency similar to that of disulfiram, suggesting that, in susceptible individuals, ingestion of large amounts of cruciferous vegetables in combination with alcohol could give rise to antabus-like symptoms.
Abstract: Phenethyl isothiocyanate (PEITC) is found in cabbages and other commonly ingested cruciferous vegetables. Isothiocyanates have anticarcinogenic properties, proposed to be mediated in part by their inhibition of several cytochrome P450 (CYP) forms. We administered PEITC to rats treated chronically with ethanol for 38 days by means of total enteral nutrition model to inhibit CYP2E1. We observed that PEITC not only efficiently prevented the ethanol-induced elevation of CYP2E1 apoprotein and mRNA, but also significantly elevated blood acetaldehyde levels. An elevation also was observed in naive animals acutely administered PEITC and ethanol, an effect found to be associated with marked inhibition of liver aldehyde dehydrogenase (ALDH). PEITC (1 mmol/kg) inhibited total liver ALDH activity by more than 70% and inhibition persisted for at least 24 hr. The inhibition was similar to that caused by an equimolar dose of disulfiram. Experiments using subcellular rat liver fractions revealed that both low- and high-Km ALDH forms were inhibited by low concentrations of PEITC (IC50 = 0.8-6.0 microM). Importantly, the mitochondrial low-Km ALDH activity, which is mainly responsible for detoxification of low aldehyde levels, was strongly inhibited (IC50 = 1.4 microM). In contrast, neither alcohol dehydrogenase nor lactate dehydrogenase activity was inhibited by PEITC. Thus, PEITC inhibits liver ALDH with a potency similar to that of disulfiram, suggesting that, in susceptible individuals, ingestion of large amounts of cruciferous vegetables in combination with alcohol could give rise to antabus-like symptoms. This property of PEITC must be taken into account in experimental alcohol research and in evaluating its proposed anticarcinogenic actions on chemical procarcinogens that are activated into potentially carcinogenic aldehydes.

Journal ArticleDOI
TL;DR: It was found that, although aldehyde dehydrogenase activity was detected in many areas of the brain, only in the cerebellar Purkinje cells was there a difference between sensitive and resistant lines of mice or rats.
Abstract: Aldehyde dehydrogenase activity in brain has been studied for many years. However, the question of its role in the actions of ethanol in the brain has not been resolved. We have utilized mice and rats selectively bred for sensitivity or resistance to the initial hypnotic effects of ethanol to gain some insight into the possible involvement of brain aldehyde dehydrogenase in the actions of ethanol. We compared the levels of aldehyde dehydrogenase activity in the brains of these selected lines of rodents by histochemical methods. It was found that, although aldehyde dehydrogenase activity was detected in many areas of the brain, only in the cerebellar Purkinje cells was there a difference between sensitive and resistant lines of mice or rats. The resistant lines (Short Sleep mice and Low Alcohol Sensitive rats) had statistically higher levels of aldehyde dehydrogenase than did the sensitive lines (Long Sleep mice and High Alcohol Sensitive rats). Although this does not prove that aldehyde dehydrogenase or aldehydes are involved in the central actions of ethanol, it provides another piece of evidence in this direction.

Luu Su1, Wang Mf, Lin Dl, Kao Mh, Chen Ml, Chiang Ch, Pai L, Yin Sj 
01 Jul 1995
TL;DR: Of the 17 subjective feeling items tested, palpitation, facial warming, effects of alcohol, and dizziness were found to be most pronounced among the mutant homozygotes, which displayed significantly higher peak ethanol levels and AUC compared to the normal homozygote.
Abstract: Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) are the major enzymes responsible for ethanol metabolism in humans. Both enzymes exhibit genetic polymorphisms among racial populations. About half of the Chinese population lack mitochondrial ALDH2 activity and such a deficiency has been believed to be a negative risk factor for the development of alcoholism. To assess ethanol and acetaldehyde metabolism in Chinese with different ALDH2 genotypes, we genotyped 273 male adults at the ADH2, ADH3, and ALDH2 loci by using polymerase chain reaction-directed mutagenesis and restriction fragment length polymorphisms. Of the 143 individuals homozygous for both the ADH2*2 and the ADH3*1 alleles, 80, 55, and 8 were identified as ALDH2*1/*1, ALDH2*1/*2, and ALDH2*/*2, respectively. Five each from the above three ALDH2 genotypic subjects underwent alcohol elimination testing. Blood ethanol and acetaldehyde levels were determined at various times up to 130 min after intaking a low dose of ethanol (0.2 g/kg body weight) by using head-space gas chromatography and high-performance liquid chromatography with fluorescence detection, respectively. The mutant homozygotes of ALDH2*2/*2 and the heterozygotes exhibited significantly higher peak acetaldehyde concentrations and also greater areas under the blood concentrations-time curve (AUC) than did the normal homozygotes of ALDH2*1/*1, with the mutant homozygotes both being the largest. The mutant homozygotes displayed significantly higher peak ethanol levels and AUC compared to the normal homozygotes. Of the 17 subjective feeling items tested, palpitation, facial warming, effects of alcohol, and dizziness were found to be most pronounced among the mutant homozygotes.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal ArticleDOI
TL;DR: Although V. harveyi aldehyde dehydrogenase is unique in terms of its high specificity for NADP+, the identification of a catalytic conserved cysteine in Vh.ALDH clearly indicates that a highly related mechanism and structure have been retained among even the most diverged alde Hyde dehydrogenases.
Abstract: Fatty aldehyde dehydrogenase (Vh.ALDH) from the luminescent bacterium, Vibrio harveyi, may be implicated in controlling luminescence as it catalyzes the oxidation of the fatty aldehyde substrate for the light-emitting reaction. On the basis of the amino-terminal sequence of Vh.ALDH, a degenerate probe was used to screen a genomic library of V harveyi in pBR322, a positive clone was selected containing the Vh.ALDH gene and expressed in Escherichia coli, and the enzyme was purified to homogeneity. Although the sequence of the V. harveyi ALDH significantly diverged from other aldehyde dehydrogenases, mutation of a conserved cysteine implicated in catalysis completely inactivated the enzyme without loss of its ability to bind nucleotides, consistent with a catalytic role for this residue. Using absorption and fluorescence assays for NAD(P)H, it was shown that NAD+ and NADP+ bound to the same site and that saturation of Vh.ALDH with NADP+ occurred with a Michaelis constant (Km = 1.4 microM) over 40 times lower than that reported for other aldehyde dehydrogenases. Although V. harveyi aldehyde dehydrogenase is unique in terms of its high specificity for NADP+, the identification of a catalytic conserved cysteine in Vh.ALDH clearly indicates that a highly related mechanism and structure have been retained among even the most diverged aldehyde dehydrogenases.

Journal ArticleDOI
TL;DR: Results of these studies indicate that MeDTC sulfone, a potential metabolite of disulfiram, is a potent, irreversible inhibitor of low Km mitochondrial ALDH.