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Showing papers on "Acyl-CoA published in 1975"


Journal ArticleDOI
TL;DR: The available evidence suggests that in the chicken, and presumably other avian species, fatty acids are synthesized in liver and are transported as triglycerides in the plasma low-density lipoproteins to the adipose tissue for storage.

291 citations


Journal ArticleDOI
27 Feb 1975-Nature
TL;DR: Enhanced rates of FFA metabolism could be expected to aggravate myocardial infarction, in which there is a loss of ATP in the poorly perfused tissue predominantly supplied by the occluded artery.
Abstract: IN physiological concentrations, circulating long chain free fatty acids (FFA) can inhibit the myocardial oxidation of glucose and are the preferred fuel of the heart in the fasted state1,2. In sufficiently high concentrations, fatty acids as the only fuel can have toxic effects on the normal perfused rat heart3. The mechanisms involved in fatty acid toxicity may include the intracellular accumulation of products of fatty acid metabolism such as acyl CoA (ref. 4), which inhibits the transfer of ATP from sites of synthesis in the mitochondria to sites of utilisation in the cytoplasm. Thus, enhanced rates of FFA metabolism could be expected to aggravate myocardial infarction, in which there is a loss of ATP in the poorly perfused tissue predominantly supplied by the occluded artery5. As an intracellular ATP deficiency is postulated to be a factor promoting release of enzymes6, increased provision of FFA to the heart should accelerate enzyme release from infarcting heart tissue. Conversely, if the rate of accumulation of FFA breakdown products were decreased by the additional provision of glucose or glucose plus insulin to promote intracellular esterification of FFA, then the rate of enzyme release should be decreased. Increased provision of glucose could also result in increased production of anaerobic ATP which could be of importance in promoting the survival of the oxygen-limited myocardium7.

86 citations


Journal ArticleDOI
TL;DR: A novel radiochemical assay for long-chain fatty acid:CoASH ligase activity (AMP) (EC 6.2.1.3) has been developed based on the conversion of [3H]CoASH to long- chain fatty acyl CoA, which was quantitatively retained on Millipore filters upon filtration of the acidified reaction mixture under conditions where the [ 3H] coASH was not retained.

33 citations


Journal ArticleDOI
TL;DR: The aggregation of the reductase and its high detergent sensitivity suggest that this enzyme is highly hydrophobic and probably buried in the membrane matrix.

31 citations


Book ChapterDOI
TL;DR: This chapter discusses the long-chain fatty acyl-CoA synthetase from rat liver microsomes, and the method of assay the formation of [ 3 H]palmitoyl- coA from [9,10- 3 H ]palmitate in the presence of purified palmitoyL- CoA synthase is described.
Abstract: Publisher Summary This chapter discusses the long-chain fatty acyl-CoA synthetase from rat liver microsomes. The overall activation reaction may be assayed by trapping the acyl-CoA formed either as a hydroxamate or as an acyl-carnitine, by CoA sulfhydryl disappearance, by PP i release, by adenosine monophosphate (AMP) release, or by following the appearance of the thio-ester bond at 232 nm. In the method of assay the formation of [ 3 H]palmitoyl-CoA from [9,10- 3 H]palmitate in the presence of purified palmitoyl-CoA synthase is described. The reaction is carried out by adding 0.1 ml of the reagent mixture to 1–5 μg of purified palmitoyl-CoA synthase (or 20–100 μg of microsomal preparation or partially purified fraction) in a final volume of 0.2 nil at 30° for 5–10 minutes. Incubation is terminated by the addition of 1 ml of Dole's medium, 0.4 ml H 2 O, and 0.6 ml of heptane. After mixing thoroughly and subsequent centrifugation, the upper phase, containing the unreacted palmitate, is withdrawn by suction and the lower phase is washed 6 times successively with 0.6 ml of n -heptane, always discarding the washings (upper phases). The lower phase is then assayed for radioactivity by scintillation counting in toluene–ethanol 2:1 scintillating fluid. In the control experiment, enzyme is added after the addition of Dole's medium.

27 citations


Journal ArticleDOI
TL;DR: The effects of fasting on the rate of fatty acid synthesis, the properties of the mitochondrial citrate transporter and on pyruvate dehydrogenase activity were investigated in host liver preparations and in “poorly differentiated” Morris hepatoma, and the identification of possible regulatory sites in the control of lipogenesis were discussed.

26 citations


Book ChapterDOI
TL;DR: This chapter discusses the enzymatic determination of long-chain fatty acyl-CoA, which consists of two main steps: enzymatics hydrolysis of longchain acyl -CoA and subsequent determination of the CoA produced.
Abstract: Publisher Summary This chapter discusses the enzymatic determination of long-chain fatty acyl-CoA. The method consists of two main steps: enzymatic hydrolysis of longchain acyl-CoA (fatty acyl-CoA + H 2 O → CoA + fatty acid) and subsequent determination of the CoA produced. Several enzymes have been reported to release CoA from long-chain acyl-CoA—that is, pigeon and rat liver fatty acid synthase, pig brain pahnityl-CoA deacylase, Escherichia coli palmityl thioesterases, rat liver microsome acyl-CoA hydrolase, and pancreatic lipase. Rat liver fatty acid synthase can be prepared easily in a highly pure form and offers a convenient basis for the assay of long-chain acyl-CoA. Fatty acid synthase hydrolyzes palmityl- and stearyl- and oleyl-CoA. The concentration of long-chain acyl-CoA in the samples to be hydrolyzed should be below 5 μ M to avoid errors resulting from micelle formation. This low concentration of long-chain CoA necessitates the use of a cycling technique to measure the concentration conveniently in a spectrophotometer. The CoA released from long-chain acyl-CoA is measured with an enzymatic cycling procedure using the reactions catalyzed by carnitine acetyltransferase [acetyl-CoA:carnitine O-acetyltransferase] (CAT) and citrate synthase (CS).

8 citations


Journal ArticleDOI
TL;DR: Inhibition of both enzymes was observed when clofibrate, or the tetrahydronapthyl analog of this drug were added in vitro, and the inhibitory effects were most pronounced on the fatty acyl CoA:cholesterol acyltransferase.

2 citations


Journal ArticleDOI
TL;DR: It is concluded that glucose administration to the fasted animal depresses hepatic gluconeogenesis, fatty acid oxidation and redirects carbon flux to triglyceride synthesis.
Abstract: 1. 1. Using a technique which allows the study of liver metabolism in situ , acute changes in hepatic metabolism were examined following intravenous administration of glucose (0·2–1·6 g per animal) to 40-hr starved anaesthetized rabbits. 2. 2. Administration of 0·8 g of glucose resulted in a 2·5-fold decrease in the ratio: relative molar specific radioactivity of 14 CO 2 from the oxidation of [1- 14 C] glucose/ relative molar specific radioactivity of 14 CO 2 from the oxidation of [6- 14 C] glucose This ratio decreased from 11·7 at a blood glucose concentration of 82 mg % to 4·6 at 240 mg %, reflecting an overall decrease in the oxidation of [1- 14 C] glucose. 3. 3. In addition, glucose administration to the starved rabbit resulted in a threefold decrease in the amount of glucose released by the liver, a threefold increase in the hepatic concentration of long chain fatty acids and long chain fatty acyl CoA derivatives and a twofold increase in the hepatic concentration of Sn- glycero -3- phosphoric acid . 4. 4. It is concluded that glucose administration to the fasted animal depresses hepatic gluconeogenesis, fatty acid oxidation and redirects carbon flux to triglyceride synthesis.