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)

Population geneticists have often determined the fitness differences that account for the dynamics of naturally occurring genetic polymorphisms. However, to understand causal aspects of evolutionary processes requires, in addition, investigation of the physiological and molecular structural differences underlying adaptively significant genetic polymorphisms. The characteristics of the alcohol dehydrogenase gene--enzyme system in Drosophila melanogaster make it well suited for this kind of study. Natural populations of this species are polymorphic for two electrophoretically detectable variants, ADHF and ADHS, of the enzyme. Structural studies reported here reveal that the two variants differ by (at least) a single amino acid replacement, threonine in ADHF for lysine in ADHS.
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PMID:Structural analysis of the ADHS electromorph of Drosophila melanogaster. 10 98

The amino acid substitution responsible for the different electrophoretic mobility of the ADHs alleloenzyme and the ADHf alleloenzyme of the alcohol dehydrogenase from a Nigerian population of Drosophila melanogaster has been established as lysine (ADHs) for threonine (ADHf). This result is discussed with reference to the charge state model of electrophoretic variation, in conjunction with other know substitutions at this locus. It is concluded that electrophoretic methods should be capable of distinguishing many alleloenzymes which have identical isoelectric points without recourse to explanations involving conformational variability.
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PMID:Chemical basis of the electrophoretic variation observed at the alcohol dehydrogenase locus of Drosophila melanogaster. 11 2

The apoenzyme and holoenzyme structures of liver alcohol dehydrogenase have been determined by X-ray methods to obtain details about coenzyme binding, substrate specificity and the catalytic mechanism. Coenzyme binding induces a conformational change of the protein which partly shields the active site from the solution. The reduced coenzyme binds in an open conformation similar to that of NAD bound to malate dehydrogenase. A hydrogen bond between Thr-178 and the carboxamide group of the coenzyme is essential for proper positioning of the nicotinamide in the active site. Coenzyme analogues in which the carboxamide group is absent or substituted with iodine bind in a different conformation and do not induce the structural change of the protein. Binding of substrate molecules has been studied in crystals obtained from an equilibrium mixture of enzyme, coenzyme and p-bromobenzyl alcohol. The oxygen atom of this substrate as well as that of the inhibitor molecules trifluoroethanol and dimethyl sulphoxide bind directly to the catalytic zinc atom. The substrate-binding region is a deep hydrophobic pocket at the bottom of which the zinc atom mediates electrophilic catalysis of alcohol oxidation.
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PMID:Coenzyme-induced conformational changes and substrate binding in liver alcohol dehydrogenase. 21 94

1. The route of l-threonine degradation was studied in four strains of the genus Pseudomonas able to grow on the amino acid and selected because of their high l-threonine aldolase activity. Growth and manometric results were consistent with the cleavage of l-threonine to acetaldehyde+glycine and their metabolism via acetate and serine respectively. 2. l-Threonine aldolases in these bacteria exhibited pH optima in the range 8.0-8.7 and K(m) values for the substrate of 5-10mm. Extracts exhibited comparable allo-l-threonine aldolase activities, K(m) values for this substrate being 14.5-38.5mm depending on the bacterium. Both activities were essentially constitutive. Similar activity ratios in extracts, independent of growth conditions, suggested a single enzyme. The isolate Pseudomonas D2 (N.C.I.B. 11097) represents the best source of the enzyme known. 3. Extracts of all the l-threonine-grown pseudomonads also possessed a CoA-independent aldehyde dehydrogenase, the synthesis of which was induced, and a reversible alcohol dehydrogenase. The high acetaldehyde reductase activity of most extracts possibly resulted in the underestimation of acetaldehyde dehydrogenase. 4. l-Serine dehydratase formation was induced by growth on l-threonine or acetate+glycine. Constitutively synthesized l-serine hydroxymethyltransferase was detected in extracts of Pseudomonas strains D2 and F10. The enzyme could not be detected in strains A1 and N3, probably because of a highly active ;formaldehyde-utilizing' system. 5. Ion-exchange and molecular exclusion chromatography supported other evidence that l-threonine aldolase and allo-l-threonine aldolase activities were catalysed by the same enzyme but that l-serine hydroxymethyltransferase was distinct and different. These results contrast with the specificities of some analogous enzymes of mammalian origin.
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PMID:Bacterial catabolism of threonine. Threonine degradation initiated by L-threonine acetaldehyde-lyase (aldolase) in species of Pseudomonas. 91 18

Sequences of 47 members of the Zn-containing alcohol dehydrogenase (ADH) family were aligned progressively, and an evolutionary tree with detailed branch order and branch lengths was produced. The alignment shows that only 9 amino acid residues (of 374 in the horse liver ADH sequence) are conserved in this family; these include eight Gly and one Val with structural roles. Three residues that bind the catalytic Zn and modulate its electrostatic environment are conserved in 45 members. Asp 223, which determines specificity for NAD, is found in all but the two NADP-dependent enzymes, which have Gly or Ala. Ser or Thr 48, which makes a hydrogen bond to the substrate, is present in 46 members. The four Cys ligands for the structural zinc are conserved except in zeta-crystallin, the sorbitol dehydrogenases, and two bacterial enzymes. Analysis of the evolutionary tree gives estimates of the times of divergence for different animal ADHs. The human class II (pi) and class III (chi) ADHs probably diverged about 630 million years ago, and the newly identified human ADH6 appeared about 520 million years ago, implying that these classes of enzymes may exist or have existed in all vertebrates. The human class I ADH isoenzymes (alpha, beta, and gamma) diverged about 80 million years ago, suggesting that these isoenzymes may exist or have existed in all primates. Analysis of branch lengths shows that these plant ADHs are more conserved than the animal ones and that class III ADHs are more conserved than class I ADHs. The rate of acceptance of point mutations (PAM units) shows that selection pressure has existed for ADHs, implying that these enzymes play definite metabolic roles.
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PMID:Progressive sequence alignment and molecular evolution of the Zn-containing alcohol dehydrogenase family. 159 44

The cDNA for the alpha-isoenzyme from rhesus monkey (Macaca mulatta) liver was cloned and expressed in yeast. The alpha-isoenzymes of human and monkey liver alcohol dehydrogenase differ from the other human and horse liver enzymes in having Met57, Ala93, and Val116 instead of Leu57, Phe93, and Leu116 in the substrate binding pocket and Gly47 instead of Arg47 near the pyrophosphate moiety of the coenzyme. The effects of these differences on the kinetic mechanism, substrate specificity, and coenzyme binding were studied with the purified, recombinant monkey alpha-isoenzyme (MmADH alpha) and mutated enzymes with Gly47 substituted with His or Arg. The mechanism appears to be random for the binding of NAD+ and ethanol and ordered for NADH and acetaldehyde, with formation of a dead-end enzyme-NADH-ethanol complex. MmADH alpha reacts 130-fold slower (V/K) with ethanol and 3-25-fold slower with 2-methyl alcohols but 20-fold faster with cyclohexanol, as compared with horse (Equus caballus) liver EE isoenzyme (EqADH). MmADH alpha is stereoselective for the R isomer of 2-butanol, whereas EqADH favors the S isomer. Both enzymes have comparable reactivity with larger primary alcohols. MmADH alpha is more reactive with secondary alcohols and has highest activity with cyclohexanol. However, it does not react with steroids such as 5 beta-androstane-17 beta-ol-3-one. Molecular modeling suggests that the differences between MmADH alpha and EqADH are a result of the substitution of Ala for Phe93 and Thr for Ser48. MmADH alpha binds NAD+ most rapidly when a group with a pK of 7.4 is unprotonated, implicating His51 in this reaction. The G47R substitution decreased the dissociation constants for NAD+ and NADH and turnover numbers only about 2-fold, whereas the G47H substitution increased dissociation constants 7-14-fold and turnover numbers 4-fold. A basic residue at position 47 is not crucial for activity, as multiple interactions determine coenzyme affinity.
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PMID:Alpha-isoenzyme of alcohol dehydrogenase from monkey liver. Cloning, expression, mechanism, coenzyme, and substrate specificity. 161 64

Preincubation of rat liver cells (the C-9 cell line) with okadaic acid (0.6 microM), a known inhibitor of protein-serine/threonine phosphate phosphatases 2A and 1, for 30 min amplified 6-keto-PGF1 alpha production stimulated by thapsigargin, thrombin, platelet activating factor (PAF), 12-O-tetradecanoylphorbol-13-acetate (TPA), the Ca2+ ionophore A-23187 and lysine-vasopressin (Lys.ADH) but not that stimulated by exogenous arachidonic acid. The amplification occurred within minutes after addition of the stimulators. The effect of preincubation was time dependent. Preincubation of the cells with okadaic acid (0.6 microM) for longer than 30 min decreased this amplification. The results suggest that inhibition of protein-serine/threonine phosphate phosphatase(s) can both positively and negatively regulate deesterification of phospholipids although the negative regulation may reflect a toxic response. Microcystin LR and nodularin, inhibitors of protein-serine/threonine phosphate phosphatases 2A and 1 in vitro, did not amplify 6-keto-PGF1 alpha production by PAF when incubated with intact cells.
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PMID:Effects of okadaic acid on agonist-stimulated PGI2 production by rat liver cells (the C-9 cell line). 164 47

Using Bacillus subtilis as a host and pTB524 as a vector plasmid, we cloned the thermostable alcohol dehydrogenase (ADH-T) gene (adhT) from Bacillus stearothermophilus NCA1503 and determined its nucleotide sequence. The deduced amino acid sequence (337 amino acids) was compared with the sequences of ADHs from four different origins. The amino acid residues responsible for the catalytic activity of horse liver ADH had been clarified on the basis of three-dimensional structure. Since those catalytic amino acid residues were fairly conserved in ADH-T and other ADHs, ADH-T was inferred to have basically the same proton release system as horse liver ADH. The putative proton release system of ADH-T was elucidated by introducing point mutations at the catalytic amino acid residues, Cys-38 (cysteine at position 38), Thr-40, and His-43, with site-directed mutagenesis. The mutant enzyme Thr-40-Ser (Thr-40 was replaced by serine) showed a little lower level of activity than wild-type ADH-T did. The result indicates that the OH group of serine instead of threonine can also be used for the catalytic activity. To change the pKa value of the putative system, His-43 was replaced by the more basic amino acid arginine. As a result, the optimum pH of the mutant enzyme His-43-Arg was shifted from 7.8 (wild-type enzyme) to 9.0. His-43-Arg exhibited a higher level of activity than wild-type enzyme at the optimum pH.
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PMID:Cloning and sequencing of the gene coding for alcohol dehydrogenase of Bacillus stearothermophilus and rational shift of the optimum pH. 173 26

The three-dimensional structure of human beta 1 beta 1 alcohol dehydrogenase (ADH; EC 1.1.1.1) complexed with NAD+ has been determined by x-ray crystallography to 3.0-A resolution. The amino acids directly involved in coenzyme binding are conserved between horse EE and human beta 1 beta 1 alcohol dehydrogenase in all but one case [serine (horse) vs. threonine (human) at position 48]. As a result, the coenzyme molecule is bound in a similar manner in the two enzymes. However, the strength of the interactions in the vicinity of the pyrophosphate bridge of NAD+ appears to be enhanced in the human enzyme. Side-chain movements of Arg-47 and Asp-50 and a shift in the position of the helix comprising residues 202-212 may explain both the decreased Vmax and the decreased rate of NADH dissociation observed in the human enzyme vs. the horse enzyme. It appears that these catalytic differences are not due to substitutions of any amino acids directly involved in coenzyme binding but are the result of structural rearrangements resulting from multiple sequence differences between the two enzymes.
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PMID:Structure of human beta 1 beta 1 alcohol dehydrogenase: catalytic effects of non-active-site substitutions. 189 63

Replacing Leu-182 by Ala in yeast alcohol dehydrogenase (YADH; alcohol:NAD+ oxidoreductase, EC 1.1.1.1) yields a mutant that retains 34% of its kcat value and makes one stereochemical "mistake" every 850,000 turnovers (instead of approximately 1 error every 7,000,000,000 turnovers in native YADH) in its selection of the 4-Re hydrogen of NADH. Half of the decrease in stereochemical fidelity comes from an increase in the rate of transfer of the 4-Si hydrogen of NADH. The mutant also accepts 5-methylnicotinamide adenine dinucleotide, a cofactor analog not accepted by native YADH. The stereospecificity of the mutant is lower still with analogs of NADH where the carboxamide group of the nicotinamide ring is replaced by groups with weaker hydrogen bonding potential. For example, with thio-NADH, the mutant enzyme makes 1 stereochemical "mistake" every 450 turnovers. Finally, the double mutant T157S/L182A, in which Thr-157 is replaced by Ser and Leu-182 is replaced by Ala, also shows decreased stereochemical fidelity. These results suggest that Si transfer in the mutant enzymes arises from NADH bound in a syn conformation in the active site and that this binding is not obstructed in native YADH by side chains essential for catalysis.
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PMID:Structural determinants of stereospecificity in yeast alcohol dehydrogenase. 192


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