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)

The pyruvate-to-ethanol pathway in Entamoeba histolytica is unusual when compared with most investigated organisms. Pyruvate decarboxylase (EC 4.1.1.1), a key enzyme for ethanol production, is not found. Pyruvate is converted into acetyl-CoA and CO2 by the enzyme pyruvate synthase (EC 1.2.7.1), which has been demonstrated previously in this parasitic amoeba. Acetyl-CoA is reduced to acetaldehyde and CoA by the enzyme aldehyde dehydrogenase (acylating) (EC 1.2.1.10) at an enzyme activity of 9 units per g of fresh cells with NADH as a reductant. Acetaldehyde is further reduced by either a previously identified NADP+-linked alcohol dehydrogenase or by a newly found NAD+-linked alcohol dehydrogenase at an enzyme activity of 136 units per g of fresh cells. Ethanol is identified as the product of soluble enzymes of amoeba acting on pyruvate or acetyl-CoA. This result is confirmed by radioactive isotopic, spectrophotometric and gas-chromatographic methods.
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PMID:Pyruvate-to-ethanol pathway in Entamoeba histolytica. 2 58

By counting the volatile molecules produced by an immobilized-enzyme catalyzed reaction which is interfaced to a mass spectrometer via a semi-permeable membrane, a general approach to biochemical measurement and detection is obtained which offers the potential of high sensitivity, specificity and speed. In combination with molecule microscopy, this method should allow, for example, a mapping of suitable enzyme distributions in non-stained and non-fixed tissue slices. Immobilized urease (urea amidohyrdrolase, EC 3.5.1.5) was used to assay urea using CO2 as the volatile product, and alcohol dehydrogenase (alcohol:NAD+ oxidoreductase, EC 1.1.1.1) was used to assay NADH using ethanol as the volatile product.
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PMID:Biochemical assay by immobilized enzymes and a mass spectrometer. 18 Oct 86

Glutamate induced the synthesis of 2-oxoglutarate dehydrogenase 50-fold during anaerobic growth of Citrobacter freundii and, in the absence of glutamate, this enzyme was even more active in cultures sparged with N2/CO2(95:5, v/v). Enzyme synthesis was partially repressed when the inlet gas was passed through heated copper but totally repressed when the inlet gas was passed through alkaline pyrogallol and reduced benzyl viologen (a treatment which would remove CO2 as well as O2). Fumarate hydratase activity also decreased but alcohol dehydrogenase and the sum of the succinate dehydrogenase and fumarate reductase activities increased when residual O2 was removed from the sparging gas. Soluble cytochromes a1 and c552.5 were detected in rigorously anaerobic cultures. Thus traces of O2 which contaminate commercial compressed N2 are sufficient to induce 2-oxoglutarate dehydrogenase synthesis and to affect significantly the synthesis and incorporation of respiratory chain components into the cytoplasmic membrane.
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PMID:Regulation of 2-oxoglutarate dehydrogenase synthesis in Citrobacter freundii by traces of oxygen in commercial nitrogen gas and by glutamate. 54 60

1. 2-Ethylhexanol was efficiently absorbed following oral administration to rats. 14C associated with 2-ethyl[1-14C]hexanol was rapidly excreted in respiratory CO2 (6-7%), faeces (8-9%) and urine (80-82%), with essentially complete elimination by 28 h after administration. 2. The amount of label recovered in 14CO2 matched the amount of unlabelled 2-heptanone plus 4-heptanone recovered from urine, suggesting that both types of metabolite may have been derived form the major urinary metabolite, 2-ethylhexanoic acid, by decarboxylation following partial beta-oxidation. The 14CO2 appeared not to be derived from acetate (urinary acetic acid and liver and brain cholesterol were not labelled) or by reductive decarboxylation (heptane was not present.) 3. Other identified metabolites were 2-ethyl-5-hydroxyhexanoic acid, 2-ethyl-5-ketohexanoic acid, and 2-ethyl-1,6-hexanedioic acid. Only about 3% of the ethylhexanol was excreted unchanged. 4. Ethylhexanol was a competitive inhibitor of yeast alcohol dehydrogenase, but a good substrate for horse alcohol dehydrogenase. 5. Other relationships between metabolism and toxicity of 2-ethylhexanol are discussed.
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PMID:The metabolism of 2-ethylhexanol in rats. 118 59

The conductance of the apical membrane of the toad urinary bladder was studied under voltage-clamp conditions at hyperpolarizing potentials (mucosa negative to serosa). The serosal medium contained high KCl concentrations to reduce the voltage and electrical resistance across the basal-lateral membrane, and the mucosal solution was Na free, or contained amiloride, to eliminate the conductance of the apical Na channels. As the mucosal potential (Vm) was made more negative the slope conductance of the epithelium increased, reaching a maximum at Vm = -100 mV. This rectifying conductance activated with a time constant of 2 msec when Vm was changed abruptly from 0 to -100 mV, and remained elevated for at least 10 min, although some decrease of current was observed. Returning Vm to +100 mV deactivated the conductance within 1 msec. Ion substitution experiments showed that the rectified current was carried mostly by cations moving from cell to mucosa. Measurement of K flux showed that the current could be accounted for by net movement of K across the apical membrane, implying a voltage-dependent conductance to K (GK). Mucosal addition of the K channel blockers TEA and Cs had no effect on GK, while 29 mM Ba diminished it slightly. Mucosal Mg (29 mM) also reduced GK, while Ca (29 mM) stimulated it. GK was blocked by lowering the mucosal pH with an apparent pKI of 4.5. Quinidine (0.5 mM in the serosal bath) reduced GK by 80%. GK was stimulated by ADH (20 mU/ml), 8-Br-cAMP (1 mM), carbachol (100 microM), aldosterone (5 X 10(-7) M for 18 hr), intracellular Li and extracellular CO2.
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PMID:Apical membrane K conductance in the toad urinary bladder. 243 Nov 46

Differential interference contrast microscopic images were used to assess the cell volume regulatory increase (VRI) response of rat IMCD segments isolated from the mid-inner medullary region of pathogen-free Sprague-Dawley rats and perfused in vitro at 37 degrees C. In the absence of ADH. IMCD cells behaved in an osmometric fashion over the range of extracellular osmolalities 290 to 386 mOsm/kg H2O and had an osmotic space equal to 54.2% of total geometric volume. After initial shrinkage in hypertonic perfusing and bathing solutions (340 mOsm/kg H2O using sucrose), cell volume increased rapidly to the isotonic value only in tubules preincubated in ADH (100 microU/ml). The rates of VIR were: (-ADH) 0.0142 +/- 0.0046 nl.min-1.cm-1 or 0.30 +/- 0.10%/min and (+ADH) 0.7225 +/- 0.1278 nl.min-1.cm-1 or 15.42 +/- 2.31%/min (N = 4; P less than 0.01). An overshoot in cell volume was observed on return to isotonic media only in the ADH exposed tubules showing a hypertonic VRI response, indicating that IMCD cells accumulated solute during hypertonic VRI. In the absence of ADH, one mM dibutyryl cyclic AMP mimicked the effect of hormone on hypertonic VRI. This ADH-dependent VRI process required Na+ and (CO2 + HCO3-) in external media and was reduced or abolished by 0.1 mM amiloride, 0.1 mM 4,4'-diisothiocyanatostilbene-2,2-'-disulfonic acid (DIDS) in peritubular solutions. These data suggest that ADH-dependent, rapid hypertonic cell volume regulation in rat inner medullary collecting duct depends on NA+ uptake, which may be mediated by parallel Na+-H+ and an HCO3(-)-dependent. DIDS-sensitive pathway (such as, Cl+-HCO3- exchanger) in basolateral cell membrane. In addition, a luminal amiloride-sensitive pathway (most likely the cation-selective channel) may contribute to cell volume regulation in the rat IMCD.
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PMID:Rapid hypertonic cell volume regulation in the perfused inner medullary collecting duct. 255 37

The physiology of Saccharomyces cerevisiae CBS 8066 was studied in glucose-limited chemostat cultures. Below a dilution rate of 0.30 h-1 glucose was completely respired, and biomass and CO2 were the only products formed. Above this dilution rate acetate and pyruvate appeared in the culture fluid, accompanied by disproportional increases in the rates of oxygen consumption and carbon dioxide production. This enhanced respiratory activity was accompanied by a drop in cell yield from 0.50 to 0.47 g (dry weight) g of glucose-1. At a dilution rate of 0.38 h-1 the culture reached its maximal oxidation capacity of 12 mmol of O2 g (dry weight)-1 h-1. A further increase in the dilution rate resulted in aerobic alcoholic fermentation in addition to respiration, accompanied by an additional decrease in cell yield from 0.47 to 0.16 g (dry weight) g of glucose-1. Since the high respiratory activity of the yeast at intermediary dilution rates would allow for full respiratory metabolism of glucose up to dilution rates close to mumax, we conclude that the occurrence of alcoholic fermentation is not primarily due to a limited respiratory capacity. Rather, organic acids produced by the organism may have an uncoupling effect on its respiration. As a result the respiratory activity is enhanced and reaches its maximum at a dilution rate of 0.38 h-1. An attempt was made to interpret the dilution rate-dependent formation of ethanol and acetate in glucose-limited chemostat cultures of S. cerevisiae CBS 8066 as an effect of overflow metabolism at the pyruvate level. Therefore, the activities of pyruvate decarboxylase, NAD+- and NADP+-dependent acetaldehyde dehydrogenases, acetyl coenzyme A (acetyl-CoA) synthetase, and alcohol dehydrogenase were determined in extracts of cells grown at various dilution rates. From the enzyme profiles, substrate affinities, and calculated intracellular pyruvate concentrations, the following conclusions were drawn with respect to product formation of cells growing under glucose limitation. (i) Pyruvate decarboxylase, the key enzyme of alcoholic fermentation, probably already is operative under conditions in which alcoholic fermentation is absent. The acetaldehyde produced by the enzyme is then oxidized via acetaldehyde dehydrogenases and acetyl-CoA synthetase. The acetyl-CoA thus formed is further oxidized in the mitochondria. (ii) Acetate formation results from insufficient activity of acetyl-CoA synthetase, required for the complete oxidation of acetate. Ethanol formation results from insufficient activity of acetaldehyde dehydrogenases.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Enzymic analysis of the crabtree effect in glucose-limited chemostat cultures of Saccharomyces cerevisiae. 256 99

At the present time, comprehensive metabolism studies of 2,3-dichloro-1-propene (2,3-DCP) have not yet been reported. We have investigated the biotransformation of 2,3-DCP using female Wistar rats in order to elucidate the bioactivation mechanisms. 175 mg/kg, 1,3-14C-2,3-DCP in corn oil was administered to a rat. The animal was killed 20 hr later. Approximately 56.7% of the radioactivity was excreted in the urine, 1.6% in the feces, 5.3% was exhaled as unchanged 2,3-DCP, and 0.3% as CO2. 31.3% remained in the organs and the carcass. Three metabolic pathways were established. 1) Conjugation with GSH leading to S-(2-chloro-2-propenyl)mercapturic acid. 2) The P450 induced epoxidation with subsequent rearrangement to highly mutagenic 1,3-dichloroacetone. 1,3-Dichloroacetone was further converted to the dimercapturic acid, 1,3-(2-propanone)-bis-S-(N-acetylcysteine). 3) The hydrolysis to 2-chloroallyl alcohol followed by alcohol dehydrogenase catalyzed formation of highly mutagenic 2-chloroacrolein. The 2-chloroallyl alcohol is excreted directly in the urine and as the glucuronide. 2-Chloroacrolein is further oxidized to 2-chloroacrylic acid which is also excreted in the urine.
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PMID:Metabolism of 2,3-dichloro-1-propene in the rat. Consideration of bioactivation mechanisms. 289 57

Cells of the aerotolerant anaerobe Giardia lamblia respire in the presence of oxygen. Endogenous respiration is stimulated by glucose but not by other carbohydrates and Krebs cycle intermediates. Endogenous and glucose-stimulated respiration are insensitive to cyanide, malonate, and 2,4-dinitrophenol, but are inhibited by atabrin and iodoacetamide. G. lamblia produces ethanol, acetate and CO2 both aerobically and anaerobically either from endogenous reserves or exogenous glucose. Molecular hydrogen is not produced. The following enzyme activities were detected in homogenates: hexokinase, fructose-biphosphate aldolase, pyruvate kinase, phosphoenolpyruvate carboxykinase, malate dehydrogenase, malate dehydrogenase (decarboxylating), pyruvate synthase, acetyl-CoA synthetase, alcohol dehydrogenase (NADP+), NADH dehydrogenase, NADPH dehydrogenase, NADPH oxidoreductase and superoxide dismutase. The enzymes of energy and carbohydrate metabolism are nonsedimentable (109 000 x g for 30 min). Activities of lactate dehydrogenase, hydrogenase, phosphate acetyltransferase, acetate kinase, citrate synthase, succinate dehydrogenase, fumarate hydratase and catalase were below the limits of detection. The results suggest the occurrence of glycolysis, energy production by substrate level phosphorylation and a flavin, iron-sulfur protein mediated electron transport system as well as the absence of cytochrome mediated oxidative phosphorylation and functional Krebs cycle.
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PMID:Energy metabolism of the anaerobic protozoon Giardia lamblia. 610 7

Urinary bladders of frogs were exposed to a transepithelial proton and osmotic gradient (serosal pH 8.1, Tris or bicarbonate buffer; mucosal pH 5.8, unbuffered) while the alkalinization rate of the mucosal bath and the net water movement were simultaneously monitored. It was observed that 1) the mucosal alkalinization rate was dependent on serosal pH and buffer; 2) oxytocin increased the mucosal alkalinization rate only when serosal bicarbonate was employed, whereas the net water movement augmented both when serosal bicarbonate or Tris buffers were used; 3) amiloride did not modify the mucosal alkalinization rate either before or after oxytocin; 4) the increases in the mucosal alkalinization rate and in the net water movement induced by oxytocin (serosal bicarbonate) were negatively correlated. In other experiments intracellular pH (pHi) was estimated with the DMO distribution technique with the following results. 1) Oxytocin increased the pHi when either serosal bicarbonate or Tris buffers was used and even in the presence of a low mucosal pH (Tris buffer, pH 5.8). 2) Important cellular acidification was observed when CO2 was bubbled (to pH 5.8), whereas the hydrosmotic response to 8-bromo-cAMP was clearly inhibited. These results indicate that cellular alkalinization could play a pivotal role in action of ADH, show that ADH can modify the transepithelial pH equilibrium mechanism, and suggest that intracellular pH regulation and water permeability control can be linked regulatory processes.
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PMID:Intracellular pH, transepithelial pH gradients, and ADH-induced water channels. 630 8


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