Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.3.1 (citrate synthase)
 4,488 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pulse-chase labeling in whole cells and cell-free protein synthesis were used to establish that the mitochondrial enzyme citrate synthase is made as a larger precursor in Saccharomyces cerevisiae. A 54,000 Mr precursor form appeared to be a primary translation product since it could be labeled with N-[35S]formylmethionine in vitro. The induction of citrate synthase was monitored in S. cerevisiae cells grown on fermentable (glucose) and nonfermentable (ethanol and glycerol) carbon sources. The amount of citrate synthase activity and immune-reactive protein increased more than 15-fold as S. cerevisiae cells entered the stationary growth phase on glucose-containing medium. This increase was paralleled by an increase in translatable RNA for the enzyme. When cells were grown on a nonfermentable carbon source, no increase in either citrate synthase or its mRNA was detected. The results suggest that the release of citrate synthase from catabolite repression may occur at the level of transcription.
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PMID:Derepression of citrate synthase in Saccharomyces cerevisiae may occur at the level of transcription. 619 62

Chronic exposure of E. coli to ethanol during growth resulted in major changes in lipid composition. These ethanol-induced changes, a decrease in the proportion of saturated fatty acids, are similar to those which occur following a shift to lower temperature. Products of ethanol metabolism such as acetaldehyde and acetate caused the opposite changes in fatty acid composition. In vivo studies using mutants blocked in lipid synthesis indicated that saturated fatty acid synthesis was the primary target leading to changes in bulk lipid fatty acid composition. This was confirmed in vitro and condensing enzyme II was identified as the probable site of ethanol inhibition. The acute affects of ethanol on the function of two membrane-bound enzymes, Mg++ATPase and lac permease were also examined. In both cases, cells grown in the presence of ethanol. In time-course studies, permease function was restored concurrently with changes in lipid composition. Mutants were isolated which were able to grow in the presence of high levels of ethanol. These mutants displayed exaggerated changes in lipid composition providing evidence that alcohol-resistance and fatty acid changes are related.
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PMID:Reversible effects of ethanol on E. coli. 644 36

Plasmid vectors for the acetic acid-producing strains of Acetobacter and Gluconobacter were constructed from their cryptic plasmids and the efficient transformation conditions were established. The systems allowed to reveal the genetic background of the strains used in the acetic acid fermentation. Genes encoding indispensable components in the acetic acid fermentation, such as alcohol dehydrogenase, aldehyde dehydrogenase and terminal oxidase, were cloned and characterized. Spontaneous mutations at high frequencies in the acetic acid bacteria to cause the deficiency in ethanol oxidation were analyzed. A new insertion sequence element, IS1380, was identified as a major factor of the genetic instability, which causes insertional inactivation of the gene encoding cytochrome c, an essential component of the functional alcohol dehydrogenase complex. Several genes including the citrate synthase gene of A. aceti were identified to confer acetic acid resistance, and the histidinolphosphate aminotransferase gene was cloned as a multicopy suppressor of an ethanol sensitive mutant. Improvement of the acetic acid productivity of an A. aceti strain was achieved through amplification of the aldehyde dehydrogenase gene with a multicopy vector. In addition, spheroplast fusion of the Acetobacter strains was developed and applied to improve their properties.
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PMID:Genetic organization of Acetobacter for acetic acid fermentation. 809 54

The effects of chronic embryonic ethanol exposure were evaluated in chick ventricular muscle. Ethanol treatments were administered on embryonic days 11, 13, 15, and 17 and chicks were sacrificed at various time points following treatments. Fluctuations in embryonic blood ethanol levels were examined following treatments. Developmental increases in the activities of mitochondrial enzymes, cytochrome oxidase (CO) and citrate synthase (CS), were observed. Ethanol exposure resulted in a depression in CO activity, but not CS activity. Since, a maximal depression in CO activity was seen with ethanol treatments of 75 mg/100 g, this dosing paradigm was adopted for subsequent experiments. A tissue-specific effect of ethanol was demonstrated as CO activity was unchanged in atrial, liver, pectoralis, and brain tissues. The role of mitochondrial DNA replication and transcription during the developmental up-regulation and ethanol-induced down-regulation of CO activity was evaluated using a cDNA probe for cytochrome oxidase subunit III (COIII). The relative levels of COIII mRNA and mitochondrial DNA (cpm/mg protein) decreased by 3-fold and 4-fold, respectively, across the developmental time course, while CO activity increased by 3.5-fold. Therefore, increases in mitochondrial DNA and mitochondrial mRNA transcripts are unlikely to be responsible for the developmentally-regulated increases in CO activity. Similarly, embryonic ethanol exposure failed to elicit alterations in COIII mRNA levels, indicating that the ethanol-induced depression in CO activity was not transcriptionally regulated. However, ventricular mitochondrial DNA concentrations were elevated in ethanol-treated embryos, indicating that ethanol-exposure either directly or indirectly induces mitochondrial DNA replication.
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PMID:Ventricular mitochondrial gene expression during development and following embryonic ethanol exposure. 838 53

Specific mitochondrial enzyme activities, mitochondrial DNA copy number, and mRNA levels were measured in heart, brain, and liver tissues of a group of alcohol-fed rats and compared with a control group. The results show a significant increase in mitochondrial enzyme activities (citrate synthase, complex IV, complex III, complex I, and complex V), as well as an increase in mitochondrial DNA in the cardiac tissue of the alcohol-fed animals. These data are indicative of an increase in mitochondrial number in the cardiac tissue that may occur as the result of an adaptive response to the alcoholic insult. However, in the liver and brain of the alcohol-treated rat, specific mitochondrial activities were decreased, in particular, complex III and ATP synthase, whereas levels of other mitochondrial enzymes (e.g., citrate synthase, specific mitochondrial transcripts, and mitochondrial DNA levels) do not seem to be affected. These data suggest that a tissue-specific response to alcohol exists that may have a common molecular mechanism in brain and liver, but is different in the heart.
Alcohol Clin Exp Res 1995 Dec
PMID:Heart mitochondria response to alcohol is different than brain and liver. 874 11

Specific mitochondrial enzyme activities and mRNA levels were measured in the heart, brain, and liver tissues of a group of 1-day-old neonatal rats whose mothers were alcohol-fed during pregnancy and compared with a control group. The results show a significant decrease in mitochondrial ATP synthase activity in both the brain and liver, as well as a decrease in complex III activity in the liver of rats exposed to alcohol. Other mitochondrial enzymes activities (e.g., citrate synthase, cytochrome c oxidase, and complex I), as well as specific mitochondrial transcript levels, were not significantly affected. Heart mitochondrial enzyme activities were not significantly affected. These data reveal that a tissue-specific response occurs after fetal exposure to alcohol and may explain some of the cellular events occurring in fetal alcohol syndrome resulting in abnormal growth and neurological development.
Alcohol Clin Exp Res 1996 Sep
PMID:Mitochondrial dysfunction after fetal alcohol exposure. 889 23

Citrate synthase (EC 4.1.3.7) was purified from the acidophilic bacterium Acetobacter europaeus to electrophoretic homogeneity. The specific activity was 228 units/mg of protein during the exponential ethanol-oxidation growth phase. The enzyme has a molecular mass of 280 kDa and is a hexamer with a subunit size of 46 kDa. The apparent K(m) values were 20 microM for oxaloacetate and 51 microM for acetyl-CoA. Unlike citrate synthase from other Gram-negative bacteria, the activity of the enzyme was inhibited by ATP, slightly enhanced by ADP and not effected by NADH. Acetate caused activation of the enzyme. The pH optimum on the citrate synthase activity in vitro was 8.1. The amino-terminal amino acid sequence of the purified enzyme was ENGKSATISLNGKDVALPVL.
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PMID:Purification and properties of citrate synthase from Acetobacter europaeus. 899 6

The biological effects of the HIV-1 accessory protein, Vpr, have been studied in yeast expression systems. In our previous study [1], employing the pCUP1-vpr copper-inducible expression cassette, Vpr was shown to cause growth arrest and structural defects. In this study yeast constitutively expressing vpr, through elevated copy number and/or elevated transcription levels, displayed no growth arrest in fermentative growth conditions while Vpr was produced at much lower levels than in the inducible expression system. However, such cells were respiratory deficient and unable to utilise ethanol or glycerol as the sole carbon source. They exhibited gross mitochondrial dysfunction displayed in the loss of respiratory chain complex I, II, III, IV and citrate synthase activities. The effects on mitochondria required a C-terminal domain of Vpr that contains a conserved amino acid sequence motif HFRIGCRHSRIG. These results suggest that the widely observed phenomenon of 'Vpr-induced growth arrest' in human cells could be due to mitochondrial dysfunction.
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PMID:HIV-1 protein Vpr causes gross mitochondrial dysfunction in the yeast Saccharomyces cerevisiae. 923 18

A combined isotopic steady state and in vivo isotopic non-steady state analysis was used to calculate tricarboxylic acid cycle flux in livers of anesthetized rats infused with ethanol. In vivo 13C NMR spectroscopy was used to non-invasively observe label turnover of [4-13C]glutamate, [4-13C]glutamine, and [2-13C]glutamate/glutamine in liver following a bolus intravenous infusion of [2-13C]ethanol. The isotopic steady state analysis of [2-13C], [3-13C], and [4-13C]glutamate isotopomers (Malloy, C. R., Sherry, A. D., and Jeffrey, F. M. H. (1988) J. Biol. Chem. 263, 6964-6971) in liver extracts was used to indirectly calculate the anaplerotic flux (0.90 +/- 0.07 x citrate synthase flux) and [2-13C]acetyl-CoA fractional enrichment (51.4 +/- 3.4%). The [4-13C]glutamate, [4-13C]glutamine, and [2-13C]glutamate fractional enrichments determined in liver extracts were 23.0 +/- 1.1, 17.2 +/- 1.5, and 7.7 +/- 0.5%, respectively. These data in addition to blood [2-13C]acetate and [4-13C]glutamine enrichment time course data were used in conjunction with a metabolic steady state mathematical analysis designed to account for liver glutamate and glutamine label dilution as a consequence of glutamine exchange with blood to calculate the tricarboxylic acid (tca) cycle flux (Vtca = 0.33 +/- 0.09 micromol/g wet weight/min) in liver. In summary, It is possible to detect 13C labeling of glutamate and glutamine in liver via non-invasive 13C NMR. Additionally, the in vivo 13C labeling kinetics of glutamate and glutamine in liver and glutamine in blood may be used to calculate the liver tricarboxylic acid cycle flux.
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PMID:In vivo 13C NMR measurements of hepatocellular tricarboxylic acid cycle flux. 957 66

The aim of this study was to investigate the interactive effects of exercise training and chronic ethanol consumption on metabolism, capillarity, and myofibrillar composition in rat limb muscles. Male Wistar rats were treated in separate groups as follows: non exercised-control; ethanol (15%) in animals' drinking water for 12 weeks; exercise training in treadmill and ethanol administration plus exercise for 12 weeks. Ethanol administration decreased capillarity and increased piruvate kinase and lactate dehydrogenase activities in white gastrocnemius; in plantaris muscle, ethanol increased citrate synthase activity and decreased cross-sectional area of type I, IIa, and IIb fibres. Exercise increased capillarity in all four limb muscles and decreased type I fibre area in plantaris. The decreased capillarity effect induced by ethanol in some muscles, was ameliorated when alcohol was combined with exercise. While alcoholic myopathy affects predominantly type IIb fibres, ethanol administration and aerobic exercise in some cases can affect type I and type IIa fibre areas. The exercise can decrease some harmful effects produced by ethanol in the muscle, including the decrease in the fibre area and capillary density.
Drug Alcohol Depend 2001 Sep 01
PMID:Effect of chronic ethanol ingestion and exercise training on skeletal muscle in rat. 1147 Mar 38


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