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)

Energy metabolism was studied in rat myocardial mitochondria by estimation of respiratory enzymes activity and content of the Krebs cycle substrates under conditions of acute and chronic intoxication with ethyl alcohol. In the acute intoxication mitochondrial redox enzymes were inhibited (glutamate- and malate dehydrogenases, NADH cytochrome C oxidoreductase and cytochrome C oxidase), succinate- and lactate dehydrogenases were activated; at the same time, contents of pyruvate, succinate, and alpha-ketoglutarate were elevated and the content of oxalacetic acid was decreased. Prolonged administration of alcohol (within 2 months) caused an intensification of glycolysis and an increase in NADH cytochrome C oxidoreductase pathway with preferable oxidation of succinate and activation of cytochrome C oxidase; the phenomenon appears to be an adaptation to chronic "alcohol hypoxia". Discontinuation of alcohol administration led to deficiency of native substrates in myocardium (primarily, oxalacetic and succinic acids) due to decrease in NAD reduction via alcohol dehydrogenase reaction and to increase in oxidation of NAD-dependent endogenous substrates.
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PMID:[Energy metabolism disorders in the myocardium due to alcoholic intoxication]. 20 87

The effect of uremia on ethanol metabolism was investigated. Uremia was induced in male Spraque-Dawley rats by removal of approximately 85 per cent of the renal mass. Control animals had a sham operation. The mean activity of alcohol dehydrogenase was markedly increased in the uremic rats to 2.12 +/- 0.13 (S.E.M.) mumoles per milligram of protein per hours as compared with a control value of 1.39 +/- 0.13 mumoles per milligram of protein per hour (p less than 0.001). There were no changes in the activity of the microsomal ethanol oxidizing system, in catalase activity present in the microsomes, or in the rates of ethanol disappearance from the blood. Uremia resulted in decreases in microsomal cytochrome -450, but no changes in cytochrome b5, NADPH-cytochrome c reductase, or in the activities of aniline hydroxylase and aminopyrine demethylase. The increase in alcohol dehydrogenase activity could not be reproduced by incubation of liver from a normal rat with uremic rat plasma, uremic human serum, or urea. Also, the increase in the enzyme activity was not associated with changes in leucocyte ascorbic acid levels. The cause and physiologic significance of the increase in alcohol dehydrogenase activity in uremia remain to be elucidated.
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PMID:Effect of uremia on rates of ethanol disappearance from the blood and on the activities of the ethanol-oxidizing enzymes. 119 57

The objective of this study was to determine whether the thiol drug, diethyldithiocarbamate (DEDC) and its two metabolites, disulfiram (DS) and carbon disulfide (CS2) could be used as inhibitors of cytochrome P-450IIE1 to protect hepatocytes from cytotoxic xenobiotics. (1) Hepatocytes isolated from rats following pyrazole administration to induce cytochrome P-450IIE1 were much more susceptible to carbon tetrachloride (CCl4) and dimethylnitrosamine (DMN) than hepatocytes from untreated rats. Microsomes isolated from P-450IIE1-induced liver were also much more effective at catalysing a NADPH-dependent metabolism of CCl4 and DMN. The activities of aniline hydroxylase and p-nitroanisole-O-demethylase increased whereas ethoxyresorufin-O-dealkylase activity was much less induced and pentoxyresorufin-O-dealkylase activity was decreased. The P-450IIE1 antibody markedly inhibited the NADPH-dependent metabolism of these compounds indicating that IIE1 is a major catalyst of the microsomal metabolism of CCl4 and DMN. (2) Hepatocytes isolated from rats treated with DEDC or its metabolites, DS and CS2, on the other hand, were resistant to CCl4 and DMN. Microsomes isolated from the liver of animals treated with DEDC or DS or CS2 were also much less effective at catalysing the NADPH-dependent metabolism of the above compounds. DEDC markedly decreased the activities of aniline hydroxylase, p-nitroanisole-O-demethylase and pentoxyresorufin-O-dealkylase but had no effect on ethoxyresorufin-O-dealkylase activity. (3) Hepatocytes isolated from pyrazole-treated rats were also more susceptible to bromobenzene (BB) and naphthalene-induced cytotoxicity than hepatocytes from untreated rats. Furthermore, DEDC or CS2 administration beforehand significantly protected hepatocytes against both xenobiotics. (4) By contrast, hepatocytes isolated from P-450IIE1 induced rats were not more susceptible to lactonitrile or cyclophosphamide. Instead, cyclophosphamide was activated by phenobarbital-induced P-450 isozymes whereas lactonitrile was activated by alcohol dehydrogenase. Hepatocytes isolated from DEDC-treated rats were also resistant to cyclophosphamide but not lactonitrile. (5) The above results suggest that P-450IIE1 catalyses the cytotoxic activation of CCl4, DMN, BB and naphthalene but not of lactonitrile or cyclophosphamide. Furthermore, the administration of DEDC and its metabolites, disulfiram or CS2, inactivates P-450IIE1 so that the hepatocytes become resistant to these hepatotoxins.
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PMID:Hepatocyte cytotoxicity induced by various hepatotoxins mediated by cytochrome P-450IIE1: protection with diethyldithiocarbamate administration. 131 44

The cytochrome P450alk gene (P45alk) from Candida tropicalis ATCC 750 was expressed in Saccharomyces cerevisiae GRF18 under control of the alcohol dehydrogenase I (ADHI) promoter. To achieve stable expression over long time periods, a 2-microns derived replicative and an integrative expression system were tested in continuous culture. The 2-microns derived replicative system could not be maintained in cells over high generation numbers. In continuous culture, the instability was more pronounced at high dilution rates (D) and high histidine concentration, for which the yeast is auxotrophic. The nature of the instability was probably due to a gene conversion event between the plasmid and the yeast chromosome. In contrast, the integrative expression system was stably maintained in cells over prolonged cultivation times. Since this work focused on the production of large quantities of P450 by heterologous expression in yeast over prolonged time periods, the integrant was used to optimize P450alk expression by varying continuous culture parameters. The P450alk expression was shown to be dependent on the D applied to the culture. The highest P450alk expression levels were obtained at high D, when cell metabolism was shifted to partial glucose oxidation, yielding ethanol as a major metabolite in the culture supernatant. In contrast, when glucose was completely oxidized at low D, the ADHI-dependent P450alk expression was reduced and followed by a corresponding decrease in heterologous protein.
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PMID:Optimization of Candida tropicalis cytochrome P450alk gene expression in Saccharomyces cerevisiae with continuous cultures. 136 75

Ethanol is oxidized in the liver by three different enzyme systems, namely by alcohol dehidrogenase (ADH), the microsomal ethanol oxidizing system and catalase. Alcohol also undergoes a first pass metabolism in the gastric mucosa due to alcohol dehydrogenase. This first pass metabolism of ethanol is decreased in the alcoholic, in the fasted state, in the elderly and during cimetidine therapy leading to elevated alcohol blood-concentrations. Ethanol toxicity is closely related to its metabolism in the liver. Ethanol oxidation by ADH generates reducing equivalents (NADH) and acetaldehyde (AA). The elevated NADH/NAD ratio results in alterations of the intermediary metabolism of lipids, carbohydrates, proteins, purines, hormones and porphyrins. Furthermore, NADH flavours free radical production. The ethanol-associated redox changes are pronounced in the perivenular zone, since this is the area of low oxygen tension and of high ADH activity. In addition to NADH, AA exerts striking toxic effects on the hepatocyte. AA binds to cellular proteins and membranes including the mitochondria, microtubules, glutathion and various enzymes. In addition, AA and lactate stimulate collagen production in fibroblasts. AA-adducts stimulate the production of antibodies against AA-epitopes and could thus aggravate the liver injury. Chronic ethanol consumption results also in the microsomal induction of a specific ethanol-inducible form of cytochrome P--450, the cytochrome P--450IIE1 with high affinity not only to ethanol but also to some drugs (acetaminophen), procarcinogens (nitrosamines) and industrial agents (carbon tetrachloride). The interaction between ethanol metabolism and the metabolism of these compounds including vitamin A may also contribute to hepatic toxicity, since the susceptibility of the alcoholic toward those compounds is enhanced.
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PMID:[Alcohol and the liver: ethanol metabolism and the pathomechanism of alcoholic liver damage]. 146 39

Cytochromes P-450 are extremely important in the oxidative metabolism of a variety of endogenous and exogenous compounds in pro- and eukaryotic organisms. Progress in understanding the structure and mechanism of action of this superfamily of enzymes has been hampered by the properties of the eukaryotic enzymes and the availability of only one well-characterized prokaryotic enzyme as a model. We report here the isolation of a Pseudomonas species which will utilize a monoterpene natural product, alpha-terpineol, as its sole source of carbon and energy. Approximately 1% of the soluble protein in the cell-free extract is a novel cytochrome P-450 (P-450terp). This enzyme and its associated iron sulfur protein electron carrier (terpredoxin) have been purified to homogeneity and their NH2-terminal amino acid sequences determined. The amino acid sequences of six tryptic peptide fragments of cytochrome P-450terp have also been determined. This sequence information was used to clone the gene encoding cytochrome P-450terp. Three clones representing approximately 8 kilobase pairs of unique sequences were selected and sequenced. Five non-overlapping open reading frames (ORFs) were found in the sequences, and the translated sequences were used to search the Protein Identification Resource for comparable proteins. The ORFs were identified as: 1) an alcohol dehydrogenase, 2) an aldehyde dehydrogenase, 3) cytochrome P-450terp, 4) terpredoxin reductase, and 5) terpredoxin. The identification of both the cytochrome P-450terp and terpredoxin DNA sequence was confirmed by the presence of each of the corresponding amino acid sequences found in the purified proteins. The five ORFs were bounded on both the 5' and 3' ends by consensus factor-independent terminator sequences. A consensus promoter sequence was found immediately 5' to the first ORF. These results indicate that we have sequenced the complete terp operon. Comparison of the amino acid sequence of cytochrome P-450terp to that of all other cytochromes P-450 has shown that it is the first member of the gene family CYP108. Preliminary characterization of the chemical and physical properties and the preparation of crystals of this new cytochrome P-450, suitable for x-ray diffraction analysis, indicate that it will be useful in comparison studies with other members of this class of proteins.
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PMID:Cytochrome P-450terp. Isolation and purification of the protein and cloning and sequencing of its operon. 162 18

The periplasmically located cytochrome c553i of Paracoccus denitrificans was purified from cells grown aerobically on choline as the carbon source. The purified protein was digested with trypsin to obtain several protein fragments. The N-terminal regions of these fragments were sequenced. On the basis of one of these sequences, a mix of 17-mer oligonucleotides was synthesized. By using this mix as a probe, the structural gene encoding cytochrome c553i (cycB) was isolated. The nucleotide sequence of this gene was determined from a genomic bank. The N-terminal region of the deduced amino acid sequence showed characteristics of a signal sequence. Based on the deduced amino acid sequence of the mature protein, the calculated molecular weight is 22,427. The gene encoding cytochrome c553i was mutated by insertion of a kanamycin resistance gene. As a consequence of the mutation, cytochrome c553i was absent from the periplasmic protein fraction. The mutation in cycB resulted in a decreased maximum specific growth rate on methanol, while the molecular growth yield was not affected. Growth on methylamine or succinate was not affected at all. Upstream of cycB the 3' part of an open reading frame (ORF1) was identified. The deduced amino acid sequence of this part of ORF1 showed homology with methanol dehydrogenases from P. denitrificans and Methylobacterium extorquens AM1. In addition, it showed homology with other quinoproteins like alcohol dehydrogenase from Acetobacter aceti and glucose dehydrogenase from both Acinetobacter calcoaceticus and Escherichia coli. Immediately downstream from cycB, the 5' part of another open reading frame (ORF2) was found. The deduced amino acid sequence of this part of ORF2 showed homology with the moxJ gene products from P. denitrificans and M. extorquens AM1.
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PMID:Isolation, sequencing, and mutagenesis of the gene encoding cytochrome c553i of Paracoccus denitrificans and characterization of the mutant strain. 165 73

The mutagenicity of nine carcinogenic N-nitrosopropylamines was studied by the Ames preincubation assay using 9000 g supernatant (S9) fractions or alcohol dehydrogenase. Treatment of animals with polychlorinated biphenyls or phenobarbital resulted in a marked increase in the ability of liver S9 to activate N-nitrosobis(2-hydroxypropyl)amine, N-nitroso(2-hydroxypropyl)(2-oxopropyl)amine, N-nitrosobis(2-oxopropyl)amine, N-nitrosobis(2-acetoxypropyl)amine, N-nitroso-2,6-dimethylmorpholine, N-nitroso(2-hydroxypropyl)methylamine, N-nitroso(2-oxopropyl)methylamine, N-nitroso(2,3-dihydroxypropyl)methylamine and N-nitroso(2,3-dihydroxypropyl)(2-hydroxypropyl)amine to mutagens, whereas 3-methylcholanthrene induction was not effective. All reactions required NADP as a cofactor for mutagenic activation, and nitrogen, carbon monoxide, cytochrome c and metyrapone considerably inhibited their mutagenic activities, whereas 7,8-benzoflavone did not. Five propanol derivatives were not mutagenic in the presence of NAD and alcohol dehydrogenase. We conclude that the phenobarbital-inducible major cytochrome P450 in liver S9 from five animal species tested was selectively involved in mutagenic activation. The same cytochrome in human liver S9 and in lung S9 from three rodent species also activated the mutagenicity of N-nitroso(2-hydroxypropyl)methylamine.
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PMID:Participation of phenobarbital-inducible cytochrome P450 in the mutagenic activation of N-nitrosopropylamines by liver and lung 9000 g fractions from five animal species and man. 185 88

The cDNA coding for the precursor protein of rat liver mitochondrial vitamin D3 25-hydroxylase, cytochrome P450LMT25, was expressed under the control of the yeast alcohol dehydrogenase I promoter and terminator in Saccharomyces cerevisiae AH22 cells. The transformed yeast cells produced a P450LMT25 protein with an almost similar apparent molecular weight as compared with that of the authentic mature enzyme. The expression level of the P450LMT25 hemoprotein was about 5 x 10(4) molecules per cell as determined by reduced CO-difference spectra. The mitochondrial fraction prepared from the transformed yeast cells exhibited both 25-hydroxylase activity toward 1 alpha-hydroxyvitamin D3 and 27-hydroxylase activity toward 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol in a reconstituted system containing bovine adrenodoxin and NADPH-adrenodoxin reductase.
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PMID:Expression of rat liver vitamin D3 25-hydroxylase cDNA in Saccharomyces cerevisiae. 201 39

Seven P450/reductase fused enzymes were produced in Saccharomyces cerevisiae by expressing fused cDNAs consisting of bovine cytochrome P450c17 (P450c17) and yeast NADPH-cytochrome P450 reductase (reductase). These fused enzymes differed in the length and amino acid sequence of the hinge region between the P450 and reductase moieties. Expression of the fused constructs under the control of the yeast alcohol dehydrogenase I promoter and terminator of expression vector pAAH5 in S. cerevisiae AH22 cells resulted in the production of about 2-8 X 10(4) molecules per cell of the seven corresponding fused enzymes. Six of the fused enzymes incorporated a protoheme, as confirmed by reduced CO-difference spectra. Recombinant yeast strains producing each of the fused hemoproteins showed P450c17-dependent 17 alpha-hydroxylase activity toward progesterone. The most active fused enzyme, delta N23FE, which lacked the amino-terminal 23 amino acids of the reductase, showed about 10 times higher 17 alpha-hydroxylase activity than bovine P450c17, although the fused enzyme (delta N23FE)' with an amino acid sequence in the hinge region different from delta N23FE was less active than delta N23FE. The fused enzyme delta N0FE, consisting of P450c17 and whole reductase, showed about 1.8 times higher activity than bovine P450c17. No activity was found with delta N84FE lacking the amino-terminal 84 amino acids of the reductase moiety. P450c17-dependent C17,(20)-lyase activity toward 17 alpha-hydroxyprogesterone was detected to lesser extents in the recombinant yeast. Fused bovine P450c17/yeast reductase enzymes show enhanced 17 alpha-hydroxylase activity, and the length and amino acid sequence in the hinge region between the P450c17 and yeast reductase moieties can be important for efficient intramolecular electron transfer in the fused enzymes.
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PMID:Genetically engineered P450 monooxygenases: construction of bovine P450c17/yeast reductase fused enzymes. 218 Apr 29


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