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)

Perfused livers from ethanol pretreated rats utilized ethanol and acetaldehyde at higher rates than appropriate controls. This adaptive increase in hepatic ethanol and acetaldehyde uptake was associated with a marked (greater than 60%) increase in hepatic oxygen uptake. Ethanol uptake in both ethanol-treated and control livers was similarly sensitive to inhibition by 4-methylpyrazole, rotenone, and antimycin A. The adaptive increase in ethanol uptake was apparently specifically abolished by ouabain, an inhibitor of the sodium-plus potassium-activated ATPase. The data are consistent with the hypothesis that chronic treatment with ethanol increases ATPase activity. The ADP produced from these initiating events enters the mitochondrial space and stimulates electron transport and oxygen uptake. As a consequence of these events, a greater rate of NADH reoxidation occurs, resulting in a greater rate of production of NAD+ which stimulates ethanol oxidation via alcohol dehydrogenase and acetaldehyde oxidation via aldehyde dehydrogenase(s).
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PMID:Common mechanism for the adaptive increase in hepatic ethanol and acetaldehyde metabolism due to chronic pretreatment with ethanol. 56 3

The rate effects of imidazole on the EE isoenzyme of horse liver alcohol dehydrogenase have been analysed in terms of the elucidated kinetic mechanism of the enzyme. These imidazole effects on both directions of the reaction within nonexcess as well as excess ranges of substrate concentrations pointed to the competition between imidazole and ethanol for binding to the same three enzyme species in the kinetic mechanism, namely the free enzyme, the enzyme-NAD+ complex, and the enzyme-NADH complex. Moreover, both imidazole and ethanol brought about an enhancement in the rate of dissociation of NAD+ from its binding site on the enzyme.
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PMID:Parallelism between ethanol and imidazole interactions with horse liver alcohol dehydrogenase. 57 85

The enzyme responsible for the stimulation by ATP AND NADPH of light emission catalyzed by bacterial luciferase has been partially purified from extracts of the luminescent bacterium, Photobacterium phosphoreum. The stimulatory activity was found to be stabilized by high concentrations of mercaptoethanol, permitting it to be separated from luciferase into an active and stable form and enabling further characterization of its functional properties. The activity of the enzyme was shown to be dependent not only on ATP and NADPH but also on the presence of a long chain fatty acid, and was inhibited by the addition of NADH and horse liver alcohol dehydrogenase. The specificity for fatty acids, as measured by the stimulation of luciferase activity, had a very limited range, with maximal luminescence being obtained with myristic acid and lower responses being observed only with tridecanoic and pentadecanoic acid. These results provide evidence in vitro for an enzyme in bioluminescent bacteria that functions as a fatty acid reductase converting fatty acids to aldehydes which in turn can be utilized by luciferase in the light-emitting reaction.
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PMID:Evidence for a fatty acid reductase catalyzing the synthesis of aldehydes for the bacterial bioluminescent reaction. Resolution from luciferase and dependence on fatty acids. 57 25

We propose a novel enzymatic method for assay of uric acid at 340 nm, which eliminates several disadvantages of both the colorimetric and enzymatic methods now in common use. Here, uric acid is catalytically oxidized to allantoin and hydrogen peroxide. The peroxide is reacted with ethanol in the presence of catalase to form acetaldehyde and water, and the acetaldehyde is reduced by NADH in the presence of alcohol dehydrogenase to ethanol. The decrease in absorbance at 340 nm caused by oxidation of NADH is directly proportional to the concentration of uric acid in the sample. Measurement of the change in absorbance between 20 and 200 s eliminates the need for a serum blank measurement. Absorbance and concentration are linearly related to 120 mg of uric acid per liter. The new method was compared with the uricase method in which decomposition of uric acid at 293 nm is directly measured. The results for the 47 patients' sera so examined can be expressed by the linear equation y340 = 1.0078x293 + 0.122 (r = 0.9984).
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PMID:New ultraviolet (340 nm) method for assay of uric acid in serum or plasma. 63 59

Reductive methylation of lysine residues activates liver alcohol dehydrogenase in the oxidation of primary alcohols, but decreases the activity of the enzyme towards secondary alcohols. The modification also desensitizes the dehydrogenase to substrate inhibition at high alcohol concentrations. Steady-state kinetic studies of methylated liver alcohol dehydrogenase over a wide range of alcohol concentrations suggest that alcohol oxidation proceeds via a random addition of coenzyme and substrate with a pathway for the formation of the productive enzyme-NADH-alcohol complex. To facilitate the analyses of the effects of methylation on liver alcohol dehydrogenase and factors affecting them, new operational kinetic parameters to describe the results at high substrate concentration were introduced. The changes in the dehydrogenase activity on alkylation were found to be associated with changes in the maximum velocities that are affected by the hydrophobicity of alkyl groups introduced at lysine residues. The desensitization of alkylated liver alcohol dehydrogenase to substrate inhibition is identified with a decrease in inhibitory Michaelis constants for alcohols and this is favoured by the steric effects of substituents at the lysine residues.
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PMID:Kinetic and mechanistic studies of methylated liver alcohol dehydrogenase. 69 32

Yeast alcohol dehydrogenase is inhibited competitively by borate with respect to NAD+. An unusual mechanism of competitive inhibition prevails: the competition for the substrate NAD+ by borate and enzyme. The following evidence supports this conclusion. (1) Much greater inhibition is observed with respect to NAD+ as compared with NADH as substrates. (2) Borate decreases the equilibrium constant of the overall reaction in the direction of ethanol oxidation, therefore, borate enters directly into the overall reaction rather than merely decreases the effectiveness of the catalyst. (3) The Ki values for unrelated enzyme reactions are identical for NAD+. (4) Stopped-flow experiments show burst kinetics only when NAD+ and borate are not premixed. (5) The Ki value is identical with the inverse of the borate-NAD+ complexation constant. (6) The pH dependence of the inhibitor demonstrates that only the B(OH)4-species is inhibiting. These results are consistent with the preferable binding of borate to NAD+ as compared with NADH. These two binding constants were found to be equal to 2000 +/- 60 and 130 +/- 8 M-1, respectively. In contrast to the liver enzyme, the yeast enzyme does not show pre-steady-state burst reactions in the reduction of NAD+. This would indicate that the interconversion of ternary complexes is at least partially rate limiting for the yeast enzyme.
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PMID:Borate inhibition of yeast alcohol dehydrogenase. 76 29

The activities of twelve enzymes were measured in crude extracts from cells of Escherichia coli K-10 grown aerobically or anaerobically in a defined medium in the presence or absence of nitrate. The activities of isocitrate dehydrogenase, aconitate hydratase, 2-oxoglutarate dehydrogenase, malate dehydrogenase, malic enzyme, and D-lactate dehydrogenase (NAD+-independent) were found to be higher in cells grown in nitrate respiration than in those in fermentation, but lower than in those in respiration. This finding may explain the incomplete oxidation in nitrate respiration and, on the other hand, suggests the operation of the tricarboxylic acid even under these conditions. The activities of succinate dehydrogenase and alcohol dehydrogenase in relation to the formation of fermentation product were as high in cells grown in fermentation as in those in respiration and were low in those in nitrate respiration. However, that ratio of the activities in the latter case to the activities in respiration was the same as the ratio for most enzymes in the tricarboxylic acid cycle. The level of lactate dehydrogenase (NAD+-dependent) was not affected by nitrate respiration but its activity in the extract was inhibited by nitrate and nitrite. The absence of lactate in the anaerobic culture with nitrate may be due to this inhibition as well as NADH oxidation by nitrate. Levels of glucose-6-phosphate dehydrogenase and glutamate dehydrogenase were not altered by the growth conditions and that of pyruvate dehydrogenase was low only in cells grown in fermentation.
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PMID:Effect of nitrate reduction on the enzyme levels in carbon metabolism in Escherichia coli. 77 52

A simple, rapid and accurate colorimetric method for the determination of ethanol in serum was studied. Ethanol is converted to acetaldehyde by alcohol dehydrogenase, and the NADH formed transfers its hydrogen through the phenazine methosulphate-p-iodonitrotetrazolium violet (PMS-INT) system to produce the red formazan which is stable and absorbs at 505 nm. The method correlates very well with an enzymatic-UV method, r=0.98 (p less than 0.001). The precision (95% limits) of the method for samples ranging from 11 to 145 mg/dl was +/-6.6%, and the recovery averaged 99%.
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PMID:Determination of ethanol in serum by an enzymatic PMS-INT colorimetric method. 84 4

A binding protein for retinal has been found in the soluble protein fraction of bovine retina. It was separable from the intracellular retinol- and retinoic acid-binding proteins by gel filtration on Sephadex G-100 and appeared to have a molecular weight of about 50,000. The new binding protein did not bind retinol or retinoic acid. The binding protein neither oxidized retinal in the presence of reduced pyridine nucleotides and is presumed, therefore, not to be a dehydrogenase. Bound retinal was reduced to retinol in the presence of liver alcohol dehydrogenase and NADH, indicating that the functional group remained accessible when in the protein complex. The binding protein bound cis isomers of retinal preferentially. Bound ligand was displaced most effectively by 11-cis-retinal. When individual cis-trans isomers of retinal were presented to the binding protein, binding was maximal with the 11-cis isomer. It is proposed that the protein be referred to as 11-cis-retinal-binding protein.
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PMID:Occurrence of a binding protein for 11-cis-retinal in retina. 86 84

The intrinsic fluorescence lifetimes of horse liver alcohol dehydrogenase (EC 1.1.1.1) and pig heart isocitrate dehydrogenase (EC 1.1.1.42) have been determined to be 5.36 ns and 4.84 ns, respectively. When reduced coenzyme is bound, the fluorescence lifetime of alcohol dehydrogenase is reduced to 4.98 ns while that of isocitrate dehydrogenase remains unchanged. Oxidized coenzymes have no effect on fluorescence lifetimes of alcohol and isocitrate dehydrogenases. This virtual constancy of protein fluorescence lifetimes has allowed the conclusion to be reached that in protein-ligand complexes with equilibrium constants in the range of 10(4)-10(6) M(-1), the static mode of quenching is substantial. The observation of resonance energy transfer in alcohol dehydrogenase-NADH complex facilitates the determination of the distance between tryptophan and the reduced nicotinamide ring involved in the transfer as 30.6 A, compared to the effective molecular radius of 36.2 A for alcohol dehydrogenase. The increased rotational relaxation times of coenzyme-bound alcohol dehydrogenase relative to the unliganded form (sigmah = 72 ns) indicate in this protein structural fluctuations occurring in the time range of nanoseconds.
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PMID:Protein fluorescence and electronic energy transfer in the determination of molecular dimensions and rotational relaxation times of native and coenzyme-bound horse liver alcohol dehydrogenase. 97 11


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