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)

Plants possess two alternative biochemical pathways for sucrose (Suc) degradation. One involves hydrolysis by invertase followed by phosphorylation via hexokinase and fructokinase, and the other route-which is unique to plants-involves a UDP-dependent cleavage of Suc that is catalyzed by Suc synthase (SuSy). In the present work, we tested directly whether a bypass of the endogenous SuSy route by ectopic overexpression of invertase or Suc phosphorylase affects internal oxygen levels in growing tubers and whether this is responsible for their decreased starch content. (a) Oxygen tensions were lower within transgenic tubers than in wild-type tubers. Oxygen tensions decreased within the first 10 mm of tuber tissue, and this gradient was steeper in transgenic tubers. (b) Invertase-overexpressing tubers had higher activities of glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase, and alcohol dehydrogenase, and (c) higher levels of lactate. (d) Expression of a low-oxygen-sensitive Adh1-beta-glucuronidase reporter gene construct was more strongly induced in the invertase-overexpressing background compared with wild-type background. (e) Intact transgenic tubers had lower ATP to ADP ratios than the wild type. ATP to ADP ratio was restored to wild type, when discs of transgenic tubers were incubated at 21% (v/v) oxygen. (f) Starch decreased from the periphery to the center of the tuber. This decrease was much steeper in the transgenic lines, leading to lower starch content especially near the center of the tuber. (g) Metabolic fluxes (based on redistribution of (14)C-glucose) and ATP to ADP ratios were analyzed in more detail, comparing discs incubated at various external oxygen tensions (0%, 1%, 4%, 8%, 12%, and 21% [v/v]) with intact tubers. Discs of Suc phosphorylase-expressing lines had similar ATP to ADP ratios and made starch as fast as wild type in high oxygen but had lower ATP to ADP ratios and lower rates of starch synthesis than wild type at low-oxygen tensions typical to those found inside an intact tuber. (h) In discs of wild-type tubers, subambient oxygen concentrations led to a selective increase in the mRNA levels of specific SuSy genes, whereas the mRNA levels of genes encoding vacuolar and apoplastic invertases decreased. (i) These results imply that repression of invertase and mobilization of Suc via the energetically less costly route provided by SuSy is important in growing tubers because it conserves oxygen and allows higher internal oxygen tensions to be maintained than would otherwise be possible.
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PMID:A bypass of sucrose synthase leads to low internal oxygen and impaired metabolic performance in growing potato tubers. 1291 61

The rate constants of the reactions of alcohol dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase with hydroxyl radicals were determined using the method of steady-state competitive reactions. Ethanol was used as a scavenger of hydroxyl radicals. The rate constants of the reactions of hydroxyl radicals with alcohol dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase were found to be 2.8 x 10(12) dm(3) mol(-1) s(-1), and 1.6 x 10(12) dm(3) mol(-1) s(-1), respectively.
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PMID:The rate constants of the reaction of hydroxyl radicals (*OH) with alcohol dehydrogenase and Glyceraldehyde-3-phosphate dehydrogenase. 1294 23

Tobacco smoke absorbed in phosphate buffer at neutral pH inhibits irreversibly the enzymes rabbit muscle glyceraldehyde-3-phosphate dehydrogenase and yeast alcohol dehydrogenase, whereas lactic dehydrogenase and glutamic dehydrogenase are not inhibited. A transient inhibition of beef liver catalase occurs. Indirect evidence suggests that the observed enzyme inhibition is caused by peroxides present in the smoke.
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PMID:Inhibiting effect of tobacco smoke on some crystalline enzymes. 1375 16

The high-resolution two-dimensional (2D) protein gel electrophoresis technique combined with matrix-assisted laser desorption ionization-time of flight mass spectrometry was used for identification of proteins whose levels were changed by a mutation in hemB. Cytoplasmic protein extracts obtained from the mutant and the wild type (strain COL) at different stages of growth in tryptone soya broth (exponential, transitional, and stationary growth phases) were separated on 2D protein gels. Comparison of the 2D patterns of the protein extracts of the two strains revealed major differences. Because the electron transport chain of the mutant is interrupted due to the deficiency of heme, this organism should be unable to use oxygen or nitrate as a terminal electron acceptor. Consistent with this hypothesis, proteins involved in the glycolytic pathway and related pathways (glyceraldehyde-3-phosphate dehydrogenase, enolase, and phosphoglycerate kinase) and in fermentation pathways (lactate dehydrogenase, alcohol dehydrogenase, and pyruvate formate lyase) were induced in exponentially growing cells of the mutant. These results strongly indicate that the hemB mutant generates ATP from glucose or fructose only by substrate phosphorylation. Analyses of the fermentation reactions showed that the main product was lactate. Although pyruvate formate lyase (Pfl) and pyruvate dehydrogenase were present, neither ethanol nor acetate was detected in significant amounts. Presumably, Pfl was not activated in the presence of oxygen, and pyruvate dehydrogenase might have very low activity. Transcriptional analysis of citB, encoding the aconitase, revealed that the activity of the citrate cycle enzymes was down-regulated in the hemB mutant. The arginine deiminase pathway was also induced, and it could provide ATP as well. Furthermore, the amounts of most of the extracellular virulence factors were significantly reduced by a mutation in hemB, which is consistent with previous reports.
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PMID:Physiological characterization of a heme-deficient mutant of Staphylococcus aureus by a proteomic approach. 1461 57

Archaeal dehydrogenases are often found to be of a specific class of dehydrogenase which has low sequence identity to the equivalent bacterial and eukaryotic counterparts. This paper focuses on two different types of hyperthermophilic dehydrogenase enzyme that have been cloned and over-expressed in Escherichia coli. The crystallographic structures of the apo form of GAPDH (glyceraldehyde-3-phosphate dehydrogenase) from Sulfolobus solfataricus and the related holo form of GAPDH from Methanothermus fervidus have been solved to high resolution. The zinc-containing structure of ADH (alcohol dehydrogenase) from Aeropyrum pernix has also been solved as a quaternary complex with the cofactor NADH and the inhibitor octanoic acid. The results show that despite the low sequence identity to the related enzymes found in other organisms the fold of the protein chain is similar. The archaeal GAPDH enzymes show a relocation of the active site which is a feature of evolutionary interest. The high thermostability of these three archaeal dehydrogenases can be attributed to a combination of factors including an increase in the number of salt bridges and hydrophobic interactions, a higher percentage of secondary structure and the presence of disulphide bonds.
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PMID:Hyperthermophilic dehydrogenase enzymes. 1504 83

Lactococcus lactis grows homofermentatively on glucose, while its growth on maltose under anaerobic conditions results in mixed acid product formation in which formate, acetate, and ethanol are formed in addition to lactate. Maltose was used as a carbon source to study mixed acid product formation as a function of the growth rate. In batch and nitrogen-limited chemostat cultures mixed acid product formation was shown to be linked to the growth rate, and homolactic fermentation occurred only in resting cells. Two of the four lactococcal strains investigated with maltose, L. lactis 65.1 and MG1363, showed more pronounced mixed acid product formation during growth than L. lactis ATCC 19435 or IL-1403. In resting cell experiments all four strains exhibited homolactic fermentation. In resting cells the intracellular concentrations of ADP, ATP, and fructose 1,6-bisphosphate were increased and the concentration of P(i) was decreased compared with the concentrations in growing cells. Addition of an ionophore (monensin or valinomycin) to resting cultures of L. lactis 65.1 induced mixed acid product formation concomitant with decreases in the ADP, ATP, and fructose 1,6-bisphosphate concentrations. ADP and ATP were shown to inhibit glyceraldehyde-3-phosphate dehydrogenase, lactate dehydrogenase, and alcohol dehydrogenase in vitro. Alcohol dehydrogenase was the most sensitive enzyme and was totally inhibited at an adenine nucleotide concentration of 16 mM, which is close to the sum of the intracellular concentrations of ADP and ATP of resting cells. This inhibition of alcohol dehydrogenase might be partially responsible for the homolactic behavior of resting cells. A hypothesis regarding the level of the ATP-ADP pool as a regulating mechanism for the glycolytic flux and product formation in L. lactis is discussed.
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PMID:The pool of ADP and ATP regulates anaerobic product formation in resting cells of Lactococcus lactis. 1534 35

Filamentous fungi are well-established expression hosts often used to produce extracellular proteins of use in the food and pharmaceutical industries. The expression systems presently used in Aspergillus species rely on either strong constitutive promoters, e.g., that for glyceraldehyde-3-phosphate dehydrogenase, or inducible systems derived from metabolic pathways, e.g., glaA (glucoamylase) or alc (alcohol dehydrogenase). We describe for Aspergillus nidulans and Aspergillus niger a novel expression system that utilizes the transcriptional activation of the human estrogen receptor by estrogenic substances. The system functions independently from metabolic signals and therefore can be used with low-cost, complex media. A combination of positive and negative regulatory elements in the promoter drives the expression of a reporter gene, yielding a linear dose response to the inducer. The off status is completely tight, yet the system responds within minutes to induction and reaches a level of expression of up to 15% of total cell protein after 8 h. Both Aspergillus species are very sensitive to estrogenic substances, and low-cost inducers function in the picomolar concentration range, at which estrogenic substances also can be found in the environment. Given this high sensitivity to estrogens, Aspergillus cells carrying estrogen-responsive units could be used to detect xenoestrogens in food or in the environment.
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PMID:Metabolically independent and accurately adjustable Aspergillus sp. expression system. 1569 16

S-Nitrosation of protein sulfhydryl groups is an established response to oxidative/nitrosative stress. The transient nature and reversibility of S-nitrosation, as well as its specificity, render this posttranslational modification an attractive mechanism of regulation of protein function and signal transduction, in analogy to S-glutathionylation. Several feasible mechanisms for protein S-nitrosation have been proposed, including transnitrosation by S-nitrosothiols, such as S-nitrosoglutathione (GSNO), where the nitrosonium moiety is directly transferred from one thiol to another. The reaction between GSNO and protein sulfhydryls can also produce a mixed disulfide by S-glutathionylation, which involves the nucleophilic attack of the sulfur of GSNO by the protein thiolate anion. In this study, we have investigated the possible occurrence of S-glutathionylation during reaction of GSNO with papain, creatine phosphokinase, glyceraldehyde-3-phosphate dehydrogenase, alcohol dehydrogenase, bovine serum albumin, and actin. Our results show that papain, creatine phosphokinase, and glyceraldehyde-3-phosphate dehydrogenase were significantly both S-nitrosated and S-glutathionylated by GSNO, whereas alcohol dehydrogenase, bovine serum albumin, and actin appeared nearly only S-nitrosated. The susceptibility of the modified proteins to denitrosation and deglutathionylation by reduced glutathione was also investigated.
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PMID:S-nitrosation versus S-glutathionylation of protein sulfhydryl groups by S-nitrosoglutathione. 1599 48

The objective of the present study was to characterize the metabolism of Clostridium thermolacticum, a thermophilic anaerobic bacterium, growing continuously on lactose (10 g l(-1)) and to determine the enzymes involved in the pathways leading to the formation of the fermentation products. Biomass and metabolites concentration were measured at steady-state for different dilution rates, from 0.013 to 0.19 h(-1). Acetate, ethanol, hydrogen and carbon dioxide were produced at all dilution rates, whereas lactate was detected only for dilution rates below 0.06 h(-1). The presence of several key enzymes involved in lactose metabolism, including beta-galactosidase, glyceraldehyde-3-phosphate dehydrogenase, pyruvate:ferredoxin oxidoreductase, acetate kinase, ethanol dehydrogenase and lactate dehydrogenase, was demonstrated. Finally, the intracellular level of NADH, NAD+, ATP and ADP was also measured for different dilution rates. The production of ethanol and lactate appeared to be linked with the re-oxidation of NADH produced during glycolysis, whereas hydrogen produced should come from reduced ferredoxin generated during pyruvate decarboxylation. To produce more hydrogen or more acetate from lactose, it thus appears that an efficient H2 removal system should be used, based on a physical (membrane) or a biological approach, respectively, by cultivating C. thermolacticum with efficient H2 scavenging and acetate producing microorganisms.
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PMID:Metabolism of lactose by Clostridium thermolacticum growing in continuous culture. 1650 46

The effect of anoxia on roots of soybean (Glycine max [L.] Merr., variety ;Williams') was studied at various levels and the results compared to those from previously studied species. While alcohol dehydrogenase (ADH) activity is induced in a manner similar to other plant species, other aspects of the anaerobic response are unique to soybean. A variety of molecular clones was used to analyze changes in soybean and maize RNA levels. Increased RNA accumulation was observed in both species with a maize ADH clone, while a maize aldolase and one of the two different maize glyceraldehyde-3-phosphate dehydrogenase cDNA clones showed induction only in maize. A maize sucrose synthase 1 clone showed induction in maize but no hybridization to soybean RNA samples. The reduction in the number of anaerobically inducible soybean genes relative to maize is consistent with in vivo and in vitro protein synthesis results. Only four major proteins are labeled during anoxia in soybean, one corresponding to ADH, while maize has been reported to have about 20. In either species, in vitro translation yields similar products with RNA from anaerobic and pre-stress plants, indicative of translational control during anoxia. These results are discussed in relation to the differential tolerance of maize and soybean to anaerobic stress.
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PMID:The anaerobic response of soybean. 1666 89


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