Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.2.1.1 (ACS)
 78,556 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. In the present paper, the two acetyl-CoA synthetases (acetate:Coenzyme A ligase (AMP-forming), EC 6.2.1.1) elaborated under aerobic or nonaerobic conditions are further differentiated by an immunological approach. 2. The subunit of the aerobic isozyme was prepared and found to be homogeneous by disc gel electrophoresis in the presence of sodium dodecyl sulfate (SDS) and by ultracentrifugal studies. An s20,w of 3.6 and an apparent molecular weight of 80,500 +/- 500 were calculated for this subunit. 3. The subunit was precipitated by antibody prepared against the aerobic enzyme. Antibody prepared against the subunit also reacted in precipitin tests with the subunit, but not with the native enzyme. The latter antibody nevertheless inhibited the native enzyme but not the nonaerobic isozyme.
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PMID:Subunit specificity of the two acetyl-CoA synthetases of yeast as revealed by an immunological approach. 610 87

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

Methanobacterium thermoautotrophicum growing on H2 plus CO2 as sole carbon and energy source was found to contain acetate thiokinase (Acetyl CoA synthetase; EC 6.2.1.1); Acetate + ATP + CoA leads to Acetyl CoA + AMP + PPi. The apparent Km value for acetate was 40 microM. Acetate kinase (EC 2.7.2.1) and phosphotransacetylase (EC 2.3.1.8) could not be detected. The specific activity of acetate thiokinase was high in cells grown with limited H2 and CO2 supply (approximately 100 nmol/min . mg protein), it was low in exponentially grown cells (2 nmol/min . mg protein). This corresponded with the finding that cells growing linearly in the presence of acetate assimilated the monocarboxylic acid in high amounts (greater than 10% of the cell carbon was derived from acetate), whereas exponentially growing cells did not (less than 1% of cell carbon was derived from acetate). These latter observations indicated that acetate thiokinase and free acetate are not involved in autotrophic CO2 fixation in M. thermoautotrophicum. The presence and some kinetic properties of succinate thiokinase (EC 6.2.1.5), adenylate kinase (EC 2.7.4.3), and inorganic pyrophosphatase (EC 3.6.1.1) are also described.
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PMID:Acetate thiokinase and the assimilation of acetate in methanobacterium thermoautotrophicum. 611

Phenylmethylsulfonyl fluoride (PMSF), a reagent commonly employed for the inhibition of serine proteases, has been found to cause significant inhibition of the incorporation of labeled acetate, but not mevalonate, into nonsaponifiable lipid and digitonin-precipitable sterols in the 10,000 X g supernatant fraction of rat liver homogenate preparations. In two experiments, the extent of inhibition of the synthesis of digitonin-precipitable sterols from acetate by PMSF at 1 mM was 81 and 65%. PMSF inhibited the synthesis of nonsaponifiable lipid from acetate at concentrations as low as 0.1 microM. Preincubation of the 10,000 X g supernatant fraction of rat liver homogenates with PMSF (1 mM) resulted in a significant reduction of the activities of acetate thiokinase and 3-hydroxy-3-methylglutaric acid (HMG)-CoA synthase, but did not affect the activities of acetoacetyl-CoA thiolase. Preincubation of rat liver microsomes with PMSF (1 mM) caused a 50% reduction in the level of HMG-CoA reductase activity. The combined results indicate that major sites of action of PMSF in the inhibition of sterol biosynthesis from labeled acetate appear to be on the activities of acetate thiokinase, HMG-CoA synthase, and HMG-CoA reductase. Another reagent used to inhibit serine proteases, diisopropylfluorophosphate, had (at a concentration of 1 mM) no effect on the activities of cytosolic acetoacetyl-CoA thiolase, HMG-CoA synthase, and HMG-CoA reductase.
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PMID:Effect of phenylmethylsulfonyl fluoride on sterol biosynthesis in 10,000 x g supernatant fraction of rat liver homogenates. 611 96

Rat liver cytoplasmic acetyl-CoA synthetase was partially purified (purification factor = 23, yield = 30%). The apparent Kms for acetate, coenzyme A, ATP and MgCl2 were determined and found to be 52.5 microM, 50.5 microM, 570 microM and 1.5 mM, respectively. The partially-purified enzyme showed a low affinity for short-chain carbon substrates other than acetate. The properties of the partially-purified enzyme were compared with those of enzymes from other sources.
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PMID:Partial purification of rat liver cytoplasmic acetyl-CoA synthetase; characterization of some properties. 614 83

A simple radiochemical assay is described for measuring the activity of rat heart mitochondrial acetyl-CoA synthase (EC 6.2.1.1) and octanoyl-CoA synthase (EC 6.2.1.2) using labelled acetate and octanoate. Separation of 14C-labelled reactant from its reaction products was achieved by lyophilization. Enzyme activity was determined by the measurement of incorporation of 14C-labelled short and medium-chain fatty acid into their CoA-derivatives. The method is applicable to the assay of other enzymes where products and substrate may be separated on the basis of the volatilization of one of them during lyophilization.
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PMID:A radiochemical assay for mitochondrial acetyl-CoA synthase and octanoyl-CoA synthase from rat heart. 615 26

The effect of hypolipidemic drugs, WY14643 and DH990, on plant lipid metabolism has been studied. The total incorporation of [14C]acetate into lipids was inhibited by addition of both drugs to aged potato (Solanum tuberosum) tuber discs, spinach (Spinacia oleracea) leaves, and spinach chloroplasts, while the incorporation in Chlorella vulgaris cells was affected only by DH990. Moreover, DH990 inhibited the incorporation of 14C-labeled fatty acids into phosphatidylcholine and phosphatidylethanolamine of potato discs, and decreased the incorporation into phosphatidylglycerol of Chlorella cells. DH990 inhibited the formation of polyunsaturated fatty acids in potato discs, Chlorella cells, and spinach leaves, whereas WY14643 had no effect on the formation of these fatty acids. Stearoyl-ACP desaturase from safflower (Carthamus tinctorius) seeds was very sensitive to both drugs, especially DH990, which completely blocked the activity at 2 mM levels. When safflower lysophospholipid acyltransferases were solubilized by detergent treatment, only DH990 inhibited the incorporation of [14C]oleoyl-CoA into lysophosphatidylcholine or lysophosphatidylethanolamine. Both drugs inhibited fatty acid synthesis from [14C]malonyl-CoA in the microsomal fraction from safflower seeds, but only DH990 inhibited FAS activity in the soluble fraction; both drugs inhibited severely the formation of stearic acid. Both acetyl-CoA carboxylase and acetyl-CoA synthetase were sensitive to both drugs.
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PMID:The effect of hypolipidemic drugs on plant lipid metabolism. 648 26

Candida tropicalis, a representative alkane- and higher fatty acid-utilizing yeast, can grow on propionate used as sole carbon and energy source. Initial pH of the medium markedly affected the growth of the yeast on propionate. In propionate-grown cells, several enzymes associated with peroxisomes and/or participating in propionate metabolism were induced in connection with the appearance of the characteristic peroxisomes. Acetate-grown cells of this yeast had only few peroxisomes, while alkane-grown cells contained conspicuous numbers of the organelles. As compared with alkane-grown cells, some specific features were observed in peroxisomes and enzymes associated with the organelles of propionate-grown cells: The shape of peroxisomes was large but the number was small; unlike localization of catalase in peroxisomes of alkane-grown cells, the enzyme of propionate-grown cells was mainly localized in cytoplasm; as for carnitine acetyltransferase localized almost equally in peroxisomes and mitochondria in alkane-grown cells, propionate-grown cells contained mainly the mitochondrial type enzyme. A propionate-activating enzyme, which was different from acetyl-CoA synthetase, was also induced in cytoplasm of propionate-grown cells. The role of carnitine acetyltransferase and the propionate-activating enzyme in propionate metabolism is discussed in comparison with the role of carnitine acetyltransferase and acetyl-CoA synthetase in acetate metabolism.
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PMID:Induction and subcellular localization of enzymes participating in propionate metabolism in Candida tropicalis. 666 Sep 94

The mode of action of carnitine on the growth of the yeast Torulopsis bovina ATCC 26014 was investigated. When 0.5-5 microM L-carnitine was added to the medium, the growth rate doubled for both aerobic and anaerobic cultures. Cells grown in the absence of carnitine contain 0.4 nmol of L-carnitine/g, wet weight, but with 5 microM L-carnitine in the media, cells contain 1400 nmol of carnitine/g, wet weight, by the end of exponential growth. When [1-14C]acetyl-L-carnitine was added to growth media, almost all of the radioactivity became cell-associated. Most of the 14C was incorporated into cell protein although considerable 14C was recovered in the fatty acid fraction of saponified cells. Analyses of the amino acids derived from radiolabeled protein showed that the acetyl[14C] of acetylcarnitine was in glutamate, arginine, proline, leucine, and lysine. In contrast, [1-14C]acetate labeled leucine and lysine. Isopycnic density gradient analysis demonstrated that carnitine acetyltransferase was primarily associated with mitochondria, while acetyl-CoA synthetase and acetyl-CoA hydrolase were cytosolic. Isolated mitochondria incorporated [14C]acetylcarnitine radioactivity into citrate and 2-oxoglutarate. The data are consistent with carnitine facilitating the transfer of acetyl groups from the cytosol into mitochondria for synthesis of citrate and its metabolites. These results demonstrate a role for carnitine in biosyntheses in the yeast T. bovina.
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PMID:A biosynthetic role for carnitine in the yeast Torulopsis bovina. 668 27

Two short-chain fatty acyl-CoA synthetases were extracted from the photosynthetic bacterium, Rhodopseudomonas sphaeroides, and partially purified by column chromatography on Sephacryl S-200 and DEAE-cellulose. One enzyme activated propionate, valerate, acrylate, butyrate, and acetate, and was designated as propionyl-CoA synthetase, since the highest activity and lowest Km value (0.6 mM) were observed with propionate. The other enzyme activated acetate, propionate and acrylate. It showed the highest activity and lowest Km value (0.37 mM) for acetate, and was identified as acetyl-CoA synthetase [EC 6.2.1.1].
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PMID:Short-chain acyl-coenzyme A synthetases in Rhodopseudomonas sphaeroides. 697 35


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