The effect of disulfiram on the aldehyde dehydrogenases of sheep liver

Kitson, Trevor M.

doi:10.1042/bj1510407

Cited by 112 publications

(60 citation statements)

References 15 publications

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“…Studies comparing the sensitivities of sheep liver cytoplasmic and mitochondrial aldehyde dehydrogenases to disulfiram [18,41] have also given close similarity to the results of Eckfeldt et al [8] with horse liver enzymes and to those of Greenfield and Pietruszko [21] with human liver enzymes. Similar differences in the Michaelis constants for NAD' have been reported for sheep [I21 and horse [8] liver cytoplasmic and mitochondrial enzymes, and the cytoplasmic enzymes from these animals show close similarity in a number of other steady-state kinetic parameters [13].…”

Section: Comparison Of' Sheep Liver Aldehyde Dehydrogenases With Othesupporting

confidence: 58%

“…Differences in the sensitivity of the two enzymes to disulfiram have also been reported [18] and recently it has been shown that the apparent rate constant for NAD+ binding is ten times faster for the cytoplasmic enzyme [16]. Thus despite their general similarities it is possible that the cytoplasmic enzyme will more rapidly oxidise available aldehyde both because of the faster rate of NADf binding and of the lower proportion of the enzyme that will be bound by NADH and hence it may be the more important enzyme in ethanol metabolism.…”

Section: C'oniporison Of' M I T O C H O N C H L Und C-ytoplusmic Enzymesmentioning

confidence: 99%

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Purification and Properties of Sheep‐Liver Aldehyde Dehydrogenases

MacGibbon

Motion

Crow

et al. 1979

European Journal of Biochemistry

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1. Sheep liver cytoplasmic aldehyde dehydrogenase was purified to homogeneity to give a sample with a specific activity of 380 nmol NADH min-' mg-'.2. An amino acid analysis of the enzyme gave results similar to those reported for aldehyde dehydrogenases from other sources. The isoelectric point was at pH 5.25 and the enzyme contained no significant amounts of metal ions.3. On the binding of NADH to the enzyme there is a shift in absorption maximum of NADH to 5. Ellman's reagent reacted only slowly with the enzyme but in the presence of sodium dodecylsulphate complete reaction occurred within a few minutes to an extent corresponding to 36 thiol groupsienzyme.6. Molecular weights were determined for both cytoplasmic and mitochondrial aldehyde dehydrogenases and were 212000 ? 8000 and 205000 respectively. Each enzyme consisted of four subunits with molecular weight of 53000 7. Properties of the cytoplasmic and mitochondria1 aldehyde dehydrogenases from sheep liver were compared with other mammalian liver aldehyde dehydrogenases. 2000.

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Section: Comparison Of' Sheep Liver Aldehyde Dehydrogenases With Othesupporting

confidence: 58%

Section: C'oniporison Of' M I T O C H O N C H L Und C-ytoplusmic Enzymesmentioning

confidence: 99%

Purification and Properties of Sheep‐Liver Aldehyde Dehydrogenases

MacGibbon

Motion

Crow

et al. 1979

European Journal of Biochemistry

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“…The general behaviouris similar to that described for the sheep liver mitochondria1 enzyme which shows a pH dependence that can be interpreted in terms of a pK, value of 8.7 [18]. Neither …”

Section: Effect Of P H On Maximum Velocitymentioning

confidence: 51%

Kinetics of Sheep‐Liver Cytoplasmic Aldehyde Dehydrogenase

MacGibbon

Blackwell

Buckley

1977

European Journal of Biochemistry

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1. Sheep liver cytoplasmic aldehyde dehydrogenase showed little pH dependence of V or k,,,. Some buffer anion effects were noted.2. The oxidation of aldehydes at pH 7.6 was quantitative but irreversible. The initial velocity data indicated a sequential mechanism for the addition of substrates. Inhibition by NADH and the product analogue 2-bromo-2-phenylacetic acid, together with the known tight binding of NADH to the free enzyme, indicated an ordered mechanism with NAD+ as leading substrate.3 . Values for the rate of binding and dissociation of NAD+ were obtained from the steady-state data. The values obtained were virtually identical with those which could be calculated from the data for the horse liver cytoplasmic enzyme. Close similarities are in general apparent for the horse and sheep liver cytoplasmic enzymes and with other tissue aldehyde dehydrogenases.4. Apparent substrate activation was observed with high concentrations of both acetaldehyde and propionaldehyde, a limiting value of 0.25 spl being obtained for k,,,. No isotope effect was observed on V using [l-'Hlpropionaldehyde as substrate suggesting that NADH release might be rate-limiting in the steady-state.5. The implications of the non-linear steady-state behaviour are discussed.In recent years aldehyde dehydrogenases from various sources have been purified to homogeneity [1,2]. More recently the purification of sheep liver cytoplasmic and mitochondrial enzymes has been reported [3] and the two major isozymes of aldehyde dehydrogenase from horse liver, which also appear to be cytoplasmic and mitochondrial in origin, have been purified and characterised [4]. An enzyme from human liver has also been studied [ 5 ] and the kinetics of aldehyde oxidation investigated, although its cellular localization is unknown.All the kinetic investigations so far reported suggest sequential mechanisms but the order of substrate addition varies from one enzyme to another. Pig brain, horse liver and bovine liver enzymes have been reported to follow compulsory order mechanisms in which NAD+ binds before aldehyde [2,6-8], but evidence has also been presented for the yeast enzyme [9] which indicates an ordered mechanism in which aldehyde binds first.The human liver enzyme appears to be partially random in its addition of its substrates, although most of the reaction is considered to proceed by means of an initial binary NAD' . enzyme complex [5]. In view of the importance of these enzymes in an understanding of human alcohol metabolism we have undertaken a detailed kinetic study of sheep liver cytoplasmic aldehyde dehydrogenase in order to determine the steady-state parameters for the reaction. MATERIALS AND METHODS MaterialsNADH (grade 111) and NAD' (grade 111) were obtained from Sigma Chemical Co. (St Louis, Mo., U.S.A.). The NADH was obtained as preweighed vials and the concentration was checked by absorbance measurements at 340 nm assuming a molar absorption coefficient (8) of 6 . 2 2~ lo3 M-l cm-I [lo]. NADt was used without further purification since no detectable...

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“…A study by Kitson et al showed that disulfiram causes an initial partial inhibition of ALDH2 followed by a gradual and irreversible loss of enzymatic activity. Kitson proposed that disulfiram forms an intermolecular mixed disulfide with one of the active thiol sites on the enzyme, thereby reducing ALDH2*1 enzyme activity [41,43]. This mechanism is represented in Figure 3A.…”

Section: Disulfiram and Alcohol Dependencementioning

confidence: 99%

Emerging Associations of the ALDH2*2 Polymorphism with Disease Susceptibility

Gueldner¹,

Sayes²,

Abel³

et al. 2016

J Drug Metab Toxicol

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Ethanol is metabolized by Alcohol Dehydrogenase (ADH) to acetaldehyde and then irreversibly oxidized by Aldehyde Dehydrogenase (ALDH) to nontoxic acetate. In individuals expressing the ALDH2*2 variant enzyme, the rate of conversion from acetaldehyde to acetate is reduced and leads to flushing, nausea, and tachycardia due to increased blood levels of acetaldehyde. The ALDH2*2 variant has a lowered NAD + coenzyme binding affinity, which results in a lowered clearance capacity toward acetaldehyde. This polymorphism is caused by the substitution of glutamate for lysine at position 487 within the catalytic active site of ALDH2, resulting in effects on subunit and quaternary complex activity. ALDH2*2 alleles are dominant over ALDH2*1 and therefore are expected to contribute to the formation of inactive heterotetramers decreased enzymatic activity in both homozygous and heterozygous individuals. Consequently, a higher susceptibility to various diseases such as Alzheimer's, osteoporosis, and acute coronary syndrome has been associated with ALDH2*2 carriers. Additionally, the polymorphism seems to affect the efficacy of Glyceryl Trinitrate (GTN), a drug intended to treat coronary heart disease, in carriers of ALDH2*2 alleles. However, the polymorphism is believed to afford a protective effect against alcoholism as the side effects of acetaldehyde build-up are undesirable. Disulfiram, a drug historically used to treat alcohol dependency, induces the same undesirable physiological effects as the variant enzyme in non-carriers by inhibiting the normal functioning of ALDH2 enzyme.

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The effect of disulfiram on the aldehyde dehydrogenases of sheep liver

Cited by 112 publications

References 15 publications

Purification and Properties of Sheep‐Liver Aldehyde Dehydrogenases

Purification and Properties of Sheep‐Liver Aldehyde Dehydrogenases

Kinetics of Sheep‐Liver Cytoplasmic Aldehyde Dehydrogenase

Emerging Associations of the ALDH2*2 Polymorphism with Disease Susceptibility

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