Showing papers on "Aldehyde dehydrogenase published in 1979"

Racial differences in alcohol sensitivity: A new hypothesis

Abstract: A hypothesis regarding alcohol sensitivity in Japanese due to a polymorphism of liver aldehyde dehydrogenase (ALDH) is presented. ALDH was found to show two major bands, a faster migrating isozyme with a low Km for acetaldehyde and a slower migrating isozyme with a high Km for acetaldehyde. Out of 40 livers of Japanese, 21 had only the slower migrating isozyme. No such variation was detected in 68 autopsy livers of Germans. Our data suggest that the initial alcohol sensitivity, quite common in individuals of Mongoloid origin, might be due to a delayed oxidation of acetaldehyde rather than its higher than normal production by atypical alcohol dehydrogenase.

Fermentation of 1,2-Propanediol and 1,2-Ethanediol by Some Genera of Enterobacteriaceae, Involving Coenzyme B12-Dependent Diol Dehydratase

Abstract: Klebsiella pneumoniae (Aerobacter aerogenes) ATCC 8724 was able to grow anaerobically on 1,2-propanediol and 1,2-ethanediol as carbon and energy sources. Whole cells of the bacterium grown anaerobically on 1,2-propanediol or on glycerol catalyzed conversion of 1,2-diols and aldehydes to the corresponding acids and alcohols. Glucose-grown cells also converted aldehydes, but not 1,2-diols, to acids and alcohols. The presence of activities of coenzyme B12-dependent diol dehydratase, alcohol dehydrogenase, coenzyme-A-dependent aldehyde dehydrogenase, phosphotransacetylase, and acetate kinase was demonstrated with crude extracts of 1,2-propanediol-grown cells. The dependence of the levels of these enzymes on growth substrates, together with cofactor requirements in in vitro conversion of these substrates, indicates that 1,2-diols are fermented to the corresponding acids and alcohols via aldehydes, acyl-coenzyme A, and acyl phosphates. This metabolic pathway for 1,2-diol fermentation was also suggested in some other genera of Enterobacteriaceae which were able to grow anaerobically on 1,2-propanediol. When the bacteria were cultivated in a 1,2-propanediol medium not supplemented with cobalt ion, the coenzyme B12-dependent conversion of 1,2-diols to aldehydes was the rate-limiting step in this fermentation. This was because the intracellular concentration of coenzyme B12 was very low in the cells grown in cobalt-deficient medium, since the apoprotein of diol dehydratase was markedly induced in the cells grown in the 1,2-propanediol medium. Better cell yields were obtained when the bacteria were grown anaerobically on 1,2-propanediol. Evidence is presented that aerobically grown cells have a different metabolic pathway for utilizing 1,2-propanediol.

Liver alcohol and aldehyde dehydrogenase: inhibition and potentiation by histamine agonists and antagonists.

Abstract: Summary 1. The in vitro effects of histamine, some other Hi- and H2-receptor agonists and some antagonists were studied on the specific activities and kinetics of rat liver alcohol dehydrogenase (ADH), and cytoplasmic and mitochondrial liver aldehyde dehydrogenase (ALDH). 2. Histamine (H1- and H2-agonist) non-competitively inhibited ADH and ALDH, 2-(2-aminoethyl) pyridine (Hi-receptor agonist) non-competitively inhibited ADH. There were no changes of cytoplasmic and mitochondrial liver ALDH activities in the presence of 2-(2-aminoethyl) pyridine. 3. Betazole (H2-receptor agonist) produced a competitive inhibition of mitochondrial ALDH but not of ADH or cytoplasmic ALDH. 4. Diphenhydramine (H1-receptor antagonist) non-competitively inhibited ADH at a lower concentration. It stimulated mitochondrial ALDH activity without changes in cytoplasmic ALDH from control values. 5. Burimamide (H2-receptor antagonist) produced a biphasic and dose-dependent stimulation and non-competitive inhibition of ADH and it non-competitively inhibited ALDH in both cytoplasmic and mitochondrial fractions. Metiamide (H2-receptor antagonist) non-competitively inhibited all ADH and ALDH of both liver fraction studied. 6. It is concluded that liver ADH and ALDH activity can be altered by compounds which affect both Hi- and H2-histamine receptors and that these compounds may cause an in vivo potentiation and/or reduction of the toxic effect of ethanol.

Purification and Properties of Sheep-Liver Aldehyde Dehydrogenases

Abstract: Sheep liver cytoplasmic aldehyde dehydrogenase was purified to homogeneity to give a sample with a specific activity of 380 nmol NADH min(-1) mg(-1). 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. On the binding of NADH to the enzyme there is a shift in absorption maximum of NADH to 344 nm, and a 5.6-fold enhancement of nucleotide fluorescence. The protein fluorescence (lambdaexcit = 290 nm, lambdaemisson = 340 nm) is quenched on the binding of NAD+ and NADH. The enhancement of nucleotide fluorescence on the binding of NADH has been utilised to determine the dissociation constant for the enzyme . NADH complex (Kd = 1.2 +/- 0.2 muM). A Hill plot of the data gave a straight line with a slope of 1.0 +/- 0.3 indicating the absence of co-operative effects. 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 groups/enzyme. Molecular weights were determined for both cytoplasmic and mitochondrial aldehyde dehydrogenases and were 212 000 +/- 8 000 and 205 000 respectively. Each enzyme consisted of four subunits with molecular weight of 53 000 +/- 2 000. Properties of the cytoplasmic and mitochondrial aldehyde dehydrogenases from sheep liver were compared with other mammalian liver aldehyde dehydrogenases.

Subcellular distribution and properties of aldehyde dehydrogenase from 2-acetylaminofluorine-induced rat hepatomas

Abstract: The subcellular distribution and properties of four aldehyde dehydrogenase isoenzymes (I-IV) identified in 2-acetylaminofluorene-induced rat hepatomas and three aldehyde dehydrogenases (I-III) identified in normal rat liver are compared. In normal liver, mitochondria (50%) and microsomal fraction (27%) possess the majority of the aldehyde dehydrogenase, with cytosol possessing little, if any, activity. Isoenzymes I-III can be identified in both fractions and differ from each other on the basis of substrate and coenzyme specificity, substrate K(m), inhibition by disulfiram and anti-(hepatoma aldehyde dehydrogenase) sera, and/or isoelectric point. Hepatomas possess considerable cytosolic aldehyde dehydrogenase (20%), in addition to mitochondrial (23%) and microsomal (35%) activity. Although isoenzymes I-III are present in tumour mitochondrial and microsomal fractions, little isoenzyme I or II is found in cytosol. Of hepatoma cytosolic aldehyde dehydrogenase activity, 50% is a hepatoma-specific isoenzyme (IV), differing in several properties from isoenzymes I-III; the remainder of the tumour cytosolic activity is due to isoenzyme III (48%). The data indicate that the tumour-specific aldehyde dehydrogenase phenotype is explainable by qualitative and quantitative changes involving primarily cytosolic and microsomal aldehyde dehydrogenase. The qualitative change requires the derepression of a gene for an aldehyde dehydrogenase expressed in normal liver only after exposure to potentially harmful xenobiotics. The quantitative change involves both an increase in activity and a change in subcellular location of a basal normal-liver aldehyde dehydrogenase isoenzyme.

Enzymatic Improvement of Food Flavor Iv

Abstract: Aldehyde oxidase (aldehyde: oxygen oxidoreductase, EC 1.2.3.1) was partially purified from bovine liver. The enzyme irreversibly oxidized various aldehydes to the corresponding acids by using dissolved oxygen as an electron acceptor. Although the Km value for n-hexanal was low (6μM), that for acetaldehyde was high (20mM). Medium-chain aldehydes such as hexanal and pentanal appear to be mainly responsible for green beany odor of soybean products. A great reduction in the beany odor was observed after the soybean extract was incubated with aldehyde oxidase under aerobic conditions. Dissolved oxygen was utilized as the electron acceptor throughout the enzyme-catalyzed oxi-dation of aldehydes and none of other cofactors were found to be required. It has been shown that bovine liver mitochondrial aldehyde dehydrogenase oxidizes the soybean protein-bound aldehyde with a rate comparable to that for free n-hexanal (Agric. Biol. Chem., 43, in press). Comparative studies of aldehyde oxidase and aldehyde dehydro-genase with respect to oxidation-rates of free aldehydes and the soybean protein-bound alde-hydes indicated that aldehyde oxidase acted on the bound aldehyde with a much slower rate.

Enzymatic Improvement of Food Flavor II. Removal of Beany Flavor from Soybean Products by Aldehyde Dehydrogenase

Abstract: Aldehyde dehydrogenase catalyzes the irreversible conversion of aldehydes into their corresponding acids. NAD-dependent aldehyde dehydrogenase purified from bovine liver mitochondria was used to remove the green beany flavor of soybean products. Incubation of the enzyme, in the presence of NAD+, with defatted soybean extracts or with soybean milk, resulted in the almost complete disappearance or in a great reduction of the flavor. It was found from experiments with pyrazole, an inhibitor of alcohol dehydrogenase, was used, that alcohols contributing to the beany flavor were converted into acids by the cooperative action of alcohol dehydrogenase and aldehyde dehydrogenase. The protein isolate prepared from the soybean extract after treatment with these enzymes produced no substantial beany flavor after storage in powdered form. Aldehyde dehydrogenase improved flavor in extract of mutton.

The separation of sheep liver cytoplasmic and mitochondrial aldehyde dehydrogenases by isoelectric focusing, and observations on the purity of preparations of the cytoplasmic enzyme, and their sensitivity towards inhibition by disulfiram.

Abstract: Preparations of sheep liver cytoplasmic aldehyde dehydrogenase obtained by published methods were found by analytical isoelectric focusing in the pH range 5--8 to contain 5--10% by weight of the mitochondrial aldehyde dehydrogenase. Under the conditions used the pI of the cytoplasmic enzyme is 6.2 and that of the mitochondrial enzyme 6.6. The mitochondrial enzyme can be removed from the preparation by selective precipitation of the cytoplasmic enzyme with (NH4)2SO4. Kinetic experiments and inhibition experiments with disulfiram show that the properties of the two sheep liver enzymes are so different that the presence of 10% mitochondrial enzyme in preparations of the cytoplasmic enzyme can introduce serious errors into results. Our results suggest that the presence of 10 microM-disulfiram in assays may completely inactivate the pure cytoplasmic enzyme. This result is in contrast with a previous report [kitson (1978) Biochem. U. 175, 83--90].

Enzymatic Improvement of Food Flavor IV. Oxidation of Aldehydes in Soybean Extracts by Aldehyde Oxidase

Abstract: Aldehyde oxidase (aldehyde: oxygen oxidoreductase, EC 1.2.3.1) was partially purified from bovine liver. The enzyme irreversibly oxidized various aldehydes to the corresponding acids by using dissolved oxygen as an electron acceptor. Although the Km value for n-hexanal was low (6 µm), that for acetaldehyde was high (20 mm).Medium-chain aldehydes such as hexanal and pentanal appear to be mainly responsible for green beany odor of soybean products. A great reduction in the beany odor was observed after the soybean extract was incubated with aldehyde oxidase under aerobic conditions. Dissolved oxygen was utilized as the electron acceptor throughout the enzyme-catalyzed oxidation of aldehydes and none of other cofactors were found to be required.It has been shown that bovine liver mitochondrial aldehyde dehydrogenase oxidizes the soybean protein-bound aldehyde with a rate comparable to that for free n-hexanal (Agric. Biol. Chem., 43, in press). Comparative studies of aldehyde oxidase and aldehyde dehydrogenas...

Improved automated kinetic determination of uric acid in serum by use of uricase/catalase/aldehyde dehydrogenase.

Abstract: The enzymatic determination of serum uric acid by use of uricase, catalase, and aldehyde dehydrogenase according to Haeckel [J. Clin. Chem. Clin Biochem. 14, 101 (1976)] showed interferences from ethanol-converting enzymes, which are present in some patients' sera. We have identified these enzymes as alcohol dehydrogenase isoenzymes. Among other substances, a mixture of pyrazole and oxalate can be used to eliminate these interferences. This inhibitor system gives good results when used in the automated kinetic uric acid determination, as is shown by a comparison with the manual assay for uric acid according to Kageyama [Clin. Chim. Acta 31, 421 (1971)].

Reversal of part of the aldehyde dehydrogenase reaction pathway during the hydrolysis of an ester.

Abstract: An aldehyde dehydrogenase from rabbit liver, a homogeneous protein on three distinct polyacrylamide-gel systems, has an associated 4-nitrophenyl esterase activity. At pH 7.0 in the presence of 80 micrometer-NADH and 800 micrometer-4-nitrophenyl acetate the enzyme produces NAD+ and a stoicheiometric amount of an aldehyde, as well as hydrolysing the ester. On this and other evidence it is proposed that ester hydrolysis occurs at the usual active site of the enzyme.

Microbial oxidation of methane and methanol: purification and properties of a heme-containing aldehyde dehydrogenase from Methylomonas methylovora

Abstract: Procedures for the purification of an aldehyde dehydrogenase from extracts of the obligate methylotroph, Methylomonas methylovora are described. The purified enzyme is homogeneous as judged from polyacrylamide gel electrophoresis. In the presence of an artificial electron acceptor (phenazine methosulfate), the purified enzyme catalyzes the oxidation of straight chain aldehydes (C1--C10 tested), aromatic aldehydes (benzaldehyde, salicylaldehyde), glyoxylate, and glyceraldehyde. Biological electron acceptors such as NAD+, NADP+, FAD, FMN, pyridoxal phosphate, and cytochrome c cannot act as electron carriers. The activity of the enzyme is inhibited by sulfhydryl agents [p-chloromercuribenzoate, N-ethylmaleimide and 5,5-dithiobis (2-nitrobenzoic acid)], cuprous chloride, and ferrour nitrate. The molecular weight of the enzyme as estimated by gel filtration is approximately 45000 and the subunit size determined by sodium dodecyl sulfate-gel electrophoresis is approximately 23000. The purified enzyme is light brown and has an absorption peak at 410 nm. Reduction of enzyme with sodium dithionite or aldehyde substrate resulted in the appearance of peaks at 523 nm and 552nm. These results suggest that the enzyme is a hemoprotein. There was no evidence that flavins were present as prosthetic group. The amino acid composition of the enzyme is also presented.

Ethanol elimination in regenerating rat liver: the roles of alcohol dehydrogenase and acetaldehyde.

Abstract: The rate of ethanol elimination in vivo was studied with rats in which the energy consumption of the liver was increased by partial hepatectomy. Immediately after partial hepatectomy the activity of alcohol dehydrogenase in the liver remnant was not changed from that of the livers of sham-operated controls, but the rate of ethanol removal was significantly faster. Twenty-four h after the partial hepatectomy the activity of alcohol dehydrogenase was only 48 % of the activity measured in unoperated control rats. Therefore it is concluded that in normal liver the activity of ADH is in excess. In partially hepatectomized rats the rate of ethanol elimination was linearly correlated with the activity of alcohol dehydrogenase, which suggests that when the rate of NADH reoxidation is markedly increased, as in regenerating rat liver, the rate of ethanol elimination may be limited by the activity of alcohol dehydrogenase. The activity of aldehyde dehydrogenase and the concentration of acetaldehyde in the tail blood were not significantly changed from the level of unoperated rats during oxidation of ethanol.

2,2'-Dithiodipyridine activates aldehyde dehydrogenase and protects the enzyme against inactivation by disulfiram.

Abstract: Small concentrations of 2,2'-dithiodipyridine cause a rapid activation of sheep liver cytoplasmic aldehyde dehydrogenase in the presence of NAD+. Enzyme pre-modified by 2,2'-dithiodipyridine is largely protected against the potent inactivatory effect of disulfiram. 2,2'-Dithiobis-(5-nitropyridine) inactivates the enzyme. The implications of these results are discussed with reference to various possible classes of thiol group in aldehyde dehydrogenase.

Enzymatic Improvement of Food Flavor III. Oxidation of the Soybean Protein-Bound Aldehyde by Aldehyde Dehydrogenase

Abstract: Defatted soybean extract was fractionated into protein fractions and low molecular weight fractions with gel filtration. NAD-dependent aldehyde dehydrogenase from bovine liver mitochondria and from yeast was found to oxidize aldehyde in both fractions. These enzymes, therefore, were used to determine the quantity of aldehyde. When the protein fraction obtained by gel filtration was subjected to gel filtration again, aldehyde was recovered in the protein fractions. The level of aldehyde in the protein fractions was unchanged before and after digestion of the protein with pepsin. When the soybean extract was incubated beforehand with aldehyde dehydrogenase and NAD+ and the subjected to gel filtration, no aldehyde was detected in the protein fractions. These results indicate that aldehyde dehydrogenase acts on the soybean protein-bound aldehyde. Alcohol dehydrogenase from horse liver in the presence of NADH did not convert the bound aldehyde to alcohol.A large portion of the aldehyde in the extract was separ...

Aldehyde dehydrogenase of the Mongolian gerbil, Meriones unguiculatus

Abstract: The aldehyde dehydrogenase (Aldehyde:NAD(P) oxidoreductase E.C. 1.2.1.3. and 1.2.1.5) phenotype in several tissues of the Mongolian gerbil, Meriones unguiculatus, has been established. The tissue distribution of gerbil aldehyde dehydrogenase is similar to that of the rat, with liver possessing the majority of the aldehyde dehydrognease activity. Male kidney and testis possess significantly more activity than female kidney and ovary. The substrate and co-enzyme specificity of gerbil liver aldehyde dehydrogenase is also similar to that of rat and mouse liver. Gel isoelectric focusing resolves one major gerbil liver aldehyde dehydrogenase isozyme at pI 5.3. Mouse liver is resolved into two major isozymes at pIs 5.3 and 5.6 and rat liver aldehyde dehydrogenase into one major isozyme at pI 5.4. Gerbil liver aldehyde dehydrogenase is functional over a broad pH range with an optima at pH 9.0. Rat and mouse liver aldehyde dehydrogenase possess sharp pH optima at pH 8.5.