Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.4.1.2 (acetyl-CoA carboxylase)
 2,876 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using stabilizing conditions the acetyl-CoA carboxylase (EC 6.4.1.2) of Pseudomonas citronellolis has been isolated as a complex containing four different polypeptide chains with molecular weights of 53 000, 36 000, 33 000 and 25 000. Evidence is presented to suggest that these polypeptide chains correspond to distinct biotin carboxylase, transcarboxylase and biotin carboxyl carrier protein subunits in analogy with similar subunits of Escherichia coli acetyl-CoA carboxylase, an unstable complex in vitro.
Biochim Biophys Acta 1976 Dec 20
PMID:Stabilization of an acetyl-coenzyme A carboxylase complex from Pseudomonas citronellolis. 1 1

Evidence is presented that rat liver microsomal fatty acid chain elongation synthesis and desaturation, as well as acetyl-CoA carboxylase and fatty acid synthetase, are strongly influenced by thyroid hormone level. Conversely, the fatty acid chain elongation system in mitochondria, unlike the oxidative capacity of palmitate, NADH, succinate and malate, does not seem significantly affected by the thyrotoxic state. In triiodothyronine-induced or thyroxine-induced hyperthyroidism, rat liver acetyl-CoA carboxylase, fatty acid synthetase and microsomal chain elongation and desaturation reactions are not greatly affected after the first 10 days of treatment, while after longer intervals a respective increase in these activities is shown of up to 87, 116 and 65% after 22 days. In propylthiouracil-induced hypothyroidism, all the above synthetic activities are strongly reduced immediately after three days of drug administration and diminished no further following longer periods. Although the pattern of synthesized fatty acids in the thyrotoxic state is similar to that obtained from normal subcellular rat fractions, the esterification process of fatty acids in microsomal lipids appears to be slightly inhibited in hypothyroid rats and increased following triiodothyronine or thyroxine administration. Finally, a reduction in the hepatic cyclic AMP level of about 41% is reported after 19 days of triiodothyronine-administration to rats. On the basis of the observed insensitivity of the mitochondrial fatty acid chain elongation system to the thyrotoxic state, a tentative interpretation of its role in the hepatic cell is postulated.
Eur J Biochem 1976 Dec
PMID:Effect of thyroid hormones on microsomal fatty acid chain elongation synthesis in rat liver. 1 55

The level of acetyl-coenzyme-A carboxylase activity in Candida lipolytica undergoes large variations depending upon the carbon source on which the yeast is grown. Cells grown on n-alkanes or fatty acids exhibit a lower activity level than do cells grown on glucose. Among the n-alkanes and fatty acids tested, n-heptadecane, n-octadecane, oleic acid and linoleic acid reduce the enzyme activity to the lowest levels, which are 16-18% of the activity level in glucose-grown cells. Immunochemical titrations and Ouchterlony double-diffusion analysis with specific antibody as well as kinetic studies have indicated that the observed decrease in the level of acetyl-CoA carboxylase activity is due to a reduction in the cellular content of the enzyme. Furthermore, isotopic leucine incorporation studies with the use of the immunoprecipitation technique have demonstrated that the relative rate of synthesis of the enzyme in oleic-acid-grown cells is diminished to 12% of that in glucose-grown cells. Evidence has also been obtained to support the view that the enzyme in this yeast is not degraded at a rate high enough to contribute to the marked decrease in the cellular content of the enzyme. Thus, it is concluded that the reduction in acetyl-CoA carboxylase content in fatty-acid-grown cells is due to diminished synthesis of the enzyme.
Eur J Biochem 1976 Dec
PMID:Acetyl-coenzyme-A carboxylase of Candida lipolytica. 2. Regulation of cellular content and synthesis of the enzyme. 1 59

The role of biotin-dependent enzymes in the fatty liver and kidney syndrome of young chicks was studied. Under conditions of a marginal deficiency of dietary biotin, the level of biotin in the liver has differing effects on the activities of two biotin-dependent enzymes, pyruvate carboxylase and acetyl-CoA carboxylase. The activity of acetyl-CoA carboxylase is increased, but when the dietary deficiency of biotin produces biotin levels which are below 0-8 mug/g of liver, the activity of pyruvate carboxylase may be insufficient to completely metabolize pyruvate via gluconeogenesis. There is an increase in liver size and in the activities of enzymes involved in alternate pathways for the removal of pyruvate. Blood lactate accumulates and there is increased synthesis of fatty acids, and an accumulation of palmitoleic acid; these steps are accomplished by increased activities of at least the following enzymes: acetyl-CoA carboxylase, malate dehydrogenase (decarboxylating) (NADP+) and the desaturase enzyme. When the biotin level is below 0-35 mug/g of liver and the chick is subjected to a stress, physiological defence mechanisms of the chick may be inadequate to maintain homeostasis and they finally collapse, resulting in accumulation of triacylglycerol in the liver and blood; the chick is unable to maintain blood glucose levels and death occurs, often only a few hours after the imposition of the stress.
Aust J Biol Sci 1976 Dec
PMID:Fatty liver and kidney syndrome in chicks. II. Biochemical role of biotin. 1 36

Intact rat epididymal fat-cells were incubated with 32Pi and the intracellular proteins separated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. One of the phosphorylated proteins has the same RF value as [14C]biotin-labelled acetyl-CoA carboxylase purified from fat-cells and is specifically precipitated after incubation with antiserum raised against acetyl-CoA carboxylase. No significant changes in the extent of phosphorylation of acetyl-CoA carboxylase were detected after exposure of the cells to insulin.
Biochem J 1977 Dec 15
PMID:Demonstration of the phosphorylation of acetyl-coenzyme A carboxylase within intact rat epididymal fat-cells. 2 37

Fatty acid synthetase was purified 13-fold from lactating rabbit mammary glands by a procedure which involved chromatography on DEAE-cellulose, ammonium sulphate precipitation and gel filtration on Sepharose 4B. The preparation was completed within two days and over 100 mg of enzyme was isolated from 100--150 g of mammary tissue, which represented a yield of over 40%. The preparation was homogeneous by the criteria of polyacrylamide gel electrophoresis and ultracentrifugal analysis. The sedimentation constant, S20,w was 13.3 S, the absorption coefficient, A280nm1%, measured refractometrically was 10.0 +/- 0.1, and the amino acid composition was determined. The subunit molecular weight determined by gel electrophoresis in the presence of sodium dodecyl sulphate was 252,000 +/- 6,000, and the molecular weight of the native enzyme measured by sedimentation equilibrium was 515,000. These experiments indicate that at the concentrations which exist in mammary tissue (2--4 mg/ml) fatty acid synthetase is a dimer. The purified enzyme did however show a tendency to dissociate to a monomeric 9-9S species on storage for several days or following exposure to a low ionic strength buffer at pH 8.3. There was only a small quantity of alkali labile phosphate (0.2 molecules per subunit) bound covalently to the purified enzyme. Acetyl-CoA carboxylase was purified 300-fold in a 50% yield within 24 h by ammonium sulphate and polyethylene glycol precipitations [Hardie, D.G. and Cohen, P. (1978) FEBS Lett. 91, 1--7]. The preparation was in a state approaching homogeneity as judged by polyacrylamide gel electrophoresis, gel filtration on Sepharose 4B and ultracentrifugal analysis. The sedimentation constant, S20,w, was 50.5 S, the absorption index, A280nm1%, was 14.5 +/- 0.7, and the amino acid composition was determined. The subunit molecular weight of acetyl-CoA carboxylase determined by gel electrophoresis in the presence of sodium dodecyl sulphate was identical to that of fatty acid synthetase (252,000) as shown by electrophoresis of a mixture of the two proteins. The preparations also contained two minor components of molecular weight 235,000 and 225,000, which appear to be derived from the major species of mol. wt 252,000. A large emount of phosphate (3.2 molecules per subunit) was found to be bound covalently to the purified enzyme. The properties of fatty acid synthetase and acetyl-CoA carboxylase are compared to those obtained by other workers.
Eur J Biochem 1978 Dec 01
PMID:Purification and physicochemical properties of fatty acid synthetase and acetyl-CoA carboxylase from lactating rabbit mammary gland. 3 36

Chick liver cell monolayers synthesize fatty acids at in vivo rates and are responsive to insulin and glucagon. High rates of fatty acid synthesis are maintained with insulin present and lost slowly without insulin. Glucagon or 3',5'-cyclic AMP cause immediate cessation of fatty acid synthesis. The site of inhibition appears to be cytoplasmic acetyl-CoA carboxylase which catalyzes the first committed step of fatty acid synthesis. Liver carboxylase exists either as catalytically inactive protomers or active filamentous polymers. Citrate, an allosteric activator of the enzyme, is required for both catalysis and polymerization. Glucagon and cAMP cause an immediate decrease in the cytoplasmic citrate concentration of chick liver cells apparently by inhibiting the conversion of glucose to citrate at the phosphofructokinase reaction. Since fatty acid synthesis and citrate level are closely correlated, citrate appears to be a feed-forward activator of the carboxylase in vivo. Compelling evidence indicates that carboxylase filaments are present in the intact cell when citrate levels are high and depolymerize when citrate levels fall. Hence, carboxylase activity and fatty acid synthetic rate appear to be determined by cytoplasmic citrate level.
CRC Crit Rev Biochem 1979 Dec
PMID:Hormonal regulation of acetyl-CoA carboxylase activity in the liver cell. 4 83

In this review, various experiments which establish the occurrence of covalent modification mechanisms, both in vivo and in vitro, in the control of acetyl-CoA carboxylase have been presented. It is interesting to note that phosphorylation of the carboxylase results in disaggregation of the active species. These studies indicate that aggregation and disaggregation of the enzyme are involved in the control of carboxylase activity. Our covalent modification mechanism and the allosteric control mechanism share a common ground in that both mechanisms affect the equilibrium between protomers and polymers of the enzyme. However, it is clear that the allosteric control mechanism cannot function alone under normal physiological conditions. Covalent modification of the carboxylase is prerequisite for efficient functioning of the allosteric mechanism. There are many aspects of the regulation of acetyl-CoA carboxylase which require further clarification. However, it is now established that short-term control of acetyl-CoA carboxylase involves the covalent modification mechanism.
Mol Cell Biochem 1979 Dec 14
PMID:Control of acetyl-CoA carboxylase by covalent modification. 4 70

2-Methylcitrate was tested in vitro on enzymes which interact with citrate and isocitrate. It was found to inhibit citrate synthase, aconitase, the NAD+- and NADP+-linked isocitrate dehydrogenase. This inhibition was competitive in nature except in the case of aconitase, and the Ki for all the enzymes was in the range of 1.5-7.6 mM. Phosphofructokinase was also inhibited by 2-methylcitrate with 50% inhibition achieved at 1 mM. ATP-citrate lyase and acetyl-CoA carboxylase were not inhibited by this compound. 2-Methylcitrate was not a substrate for ATP-citrate lyase. Acetyl-CoA carboxylase was activated by 2-methylcitrate with a Ka of 2.8 mM. The apparent Km (3.3 mM) for 2-methylcitrate for the mitochondrial citrate transporter was about 10-fold higher than the apparent Km (0.26 mM) for citrate. The tricarboxylase carrier can also be inhibited by low concentrations (0.2 mM) of 2-methylcitrate when the concentration of citrate is close to the apparent Km. Accumulation of 2-methylcitrate inside the mitochondrion, therefore, might lead to inhibition of enzymes in the citric acid cycle and thereby contribute to the ketogenesis and hypoglycemia seen under these conditions.
Pediatr Res 1975 Dec
PMID:Effect of 2-methylcitrate on citrate metabolism: implications for the management of patients with propionic acidemia and methylmalonic aciduria. 12 73

1. Rats were fed on a diet containing ethyl p-chlorophenoxyisobutyrate (0.3%, w/w) for 14 days. 2. The alterations of contents of intermediates in the liver indicate that gluconeogenesis is inhibited at the reaction(s) between 3-phosphoglycerate and fructose 1,6-diphosphate. The [nad+]/([nadh] ratios in cytoplasm and mitochondria were increased about 3- and 4-fold, respectively. Marked increases in the contents of CoA and its thioesters were found. 3. Hepatic fatty acid synthesis increased about 3-fold. There was no evidence of inhibition of the acetyl-CoA carboxylase [EC 6.4.1.2] reaction by the drug.
J Biochem 1975 Dec
PMID:Effects of ethyl p-chlorophenoxyisobutyrate on carbohydrate and fatty acid metabolism in rat liver. 17 43


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