Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

The biotin carboxyl carrier protein (BCCP) component of Escherichia coli acetyl coenzyme A carboxylase and three peptides derived from BCCP by proteolytic digestion have been examined by circular dichroism spectroscopy. BCCP, which has a peptide molecular weight of 22,500, has a spectrum typical of globular proteins with negative extrema at 222 nm and 208 nm. The two smallest peptides, BCCP(SC) and BCCP(9,100), with molecular weights of 8,900 and 9,100, respectively, exhibit unusual positive CD bands centered at 237 nm and 220 nm. BCCP(10,400), with a molecular weight of 10,400, has a CD spectrum intermediate between BCCP and that of the smallest peptides. Since d-biotin exhibits a positive CD band at 233 nm, it was suspected that the biotin prosthetic group might be the chromophore responsible for the 237 nm CD band seen in BCCP(SC) and BCCP(9,100). Enzymatic carboxylation of BCCP(SC) to form CO2-BCCP(SC) caused the CD spectrum to change with a shift of the 237 nm band to 232 nm. The positive CD band at 220 nm was unaffected by carboxylation of the biotin prosthetic group. These date suggest that the 237 nm signal may be due either to the biotin which acts as a chromophore directly or to a chromophore that is perturbed by the carboxylation of biotin. A spectropolarimetric titration was carried out to investigate the possible contribution of the single tyrosine residue of BCCP(SC) to the CD spectrum of this peptide. At pH values over 9 the CD spetrum changed with the disappearance of the 237 nm band, suggesting that tyrosine might contribute to this CD band. Denaturation of BCCP(SC) or BCCP(9,100) with 8 M urea of 6 M guanidine HCl abolished the positive CD bands and resulted in spectra typical of a random coil, whereas treatment of BCCP(SC) with 1% sodium dodecyl sulfate abolished the positive bands and left a spectrum exhibiting a shoulder at 222 nm and a negative band at 205 nm, suggestive of a high degree of ordered structure. It is concluded that the CD band at 237 nm in BCCP(SC) and BCCP(9,100) is prabably due to a noncovalent interaction of biotin with an amino acid residue(s) of the protein. It is suggested that the biotin prosthetic group is partially buried in the surface of the protein, rather than swinging free at the end of the lysine side chain through which it is covalently linked to the protein, to permit this interaction to occur.
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PMID:Acetyl coenzyme A carbosylase. Circular dichroism studies of Escherichia coli biotin carboxyl carrier protein. 0 38

The process leading to the rise of acetyl-CoA carboxylase activity in rat mammary tissue after the onset of lactation was investigated. The kinetics of change in enzyme activity and enzyme immunotitratable with antibody against avian liver acetyl-CoA carboxylase were determined during the course of lactogenic differentiation. The antibody inactivates and specifically precipitates acetyl-CoA carboxylase from rat mammary tissue as well as that from chicken liver cytosol. Characterization of the immunoprecipitate of the mammary tissue carboxylase by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis reveals a single biotin-containing polypeptide of about 230000mol.wt. This molecular weight is approximately twice that reported for the avian liver enzyme. However, chicken liver cytosol prepared in the presence of trypsin inhibitor and subjected to immunoprecipitation gives rise to a biotin-containing subunit of 230000mol.wt. as determined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis; omission of proteinase inhibitor leads to a subunit(s) approximately one-half this size. Throughout gestation both carboxylase activity and amounts of immunotitratable enzyme remained low; however, after parturition both parameters rose concomitantly to values 30-40 times the initial values. Therefore the elevated concentration of acetyl-CoA carboxylase appears to result from an increased rate of synthesis of enzyme relative to degradation rather than to activation of a pre-existing form of the enzyme.
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PMID:Changes in mammary-gland acetyl-coenzyme A carboxylase associated with lactogenic differentiation. 1 88

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.
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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.
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PMID:Purification and physicochemical properties of fatty acid synthetase and acetyl-CoA carboxylase from lactating rabbit mammary gland. 3 36

2-Methyl-2-[p-(1,2,3,4-tetrahydro-1-naphthyl)phenoxy]propionic acid (TPIA), an acetyl coenzyme A carboxylase inhibitor, blocks the aldosterone-induced increase in transepithelial sodium transport. To examine the requirement for ongoing fatty acid synthesis and/or elongation in the aldosterone-induced alteration of cellular protein metabolism in the toad's urinary bladder, the effect of TPIA has been examined in double-labeled amino acid incorporation experiments. TPIA itself has no effect on the pattern of protein labeling in either the "soluble" or a plasma membrane-enriched fraction. However, inhibition of fatty acid synthesis selectively inhibits the aldosterone-induced incorporation of membrane proteins without altering the labeling of soluble cell protein. These results indicate that ongoing fatty acid synthesis is required for the hormone-induced changes in plasma membrane protein metabolism.
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PMID:Inhibition of fatty acid synthesis prevents the incorporation of aldosterone-induced proteins into membranes. 10 29

The biotin-protein populations in several bacterial strains were analyzed by solubilization of [3H]biotin-labeled cells with sodium dodecylsulfate followed by electrophoresis on polyacrylamide gels containing the detergent. A variety of patterns of biotin-labeled polypeptide chains was seen, ranging from a single biotin-protein in Escherichia coli, corresponding to the biotin carboxyl carrier protein component of acetyl-CoA carboxylase, to multiple species in Enterobacter aerogenes, Pseudomonas citronellolis, Bacillus cereus, Propionibacterium shermanii, Lactobacillus plantarum, and Mycobacterium phlei, which probably represent subunits of multiple biotin-dependent enzymes present in these organisms. In the case of Pseudomonas citronellolis two major biotin-containing polypeptides with approximate molecular weights of 65 000 and 25 000 were shown to correspond to the biotin carboxyl carrier components of pyruvate carboxylase and acetyl-CoA carboxylase, respectively. Thus in the case of Pseudomonas citronellolis two different biotin-dependent enzymes in the same cell do not share common biotin carboxyl carrier subunits.
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PMID:Analysis of bacterial biotin-proteins. 23 15

A correlation study of the effects of two agents, 2-methyl-2-[p-(1,2,3,4-tetrahydro-1-naphthyl)phenoxy]propionic acid (TPIA) and amiloride, on aldosterone-induced alterations in Na+ transport, lipid synthesis, and phospholipid fatty acid composition has been carried out in the toad urinary bladder. TPIA, an inhibitor of acetyl-CoA carboxylase, inhibits aldosterone-stimulated Na+ transport as well as hormone-induced lipid synthesis and the increase in weight percentage of phospholipid long-chain polyunsaturated fatty acids. Amiloride, a diuretic which blocks sodium entry into the transporting epithelium, does not alter aldosterone's effects on lipid and fatty acid metabolism but prevents the hormone-induced increase in Na+ transport. These results support the conclusion that aldosterone increases Na+ transport in the toad urinary bladder by altering membrane fatty acid metabolism and that the lipid biosynthetic events following aldosterone treatment are a primary response to the hormone and not secondary to increased Na+ transport.
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PMID:Effects of an acetyl-coenzyme A carboxylase inhibitor and a sodium-sparing diuretic on aldosterone-stimulated sodium transport, lipid synthesis, and phospholipid fatty acid composition in the toad urinary bladder. 23 74

Propionyl-CoA carboxylase (EC 6.4.1.3) has been purified from Mycobacterium smegmatis. It has a molecular weight of about 500,000. On sodium dodecyl sulfate gels it dissociates into two subunits with molecular weights of 64,000 and 57,000. There are 3.8 mol of biotin/500,000 g of protein. The biotin is associated entirely with the heavier subunit. The enzyme also used acetyl-CoA as a substrate. No other acetyl-CoA carboxylase could be detected in this organism.
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PMID:Purification and subunit structure of propionyl coenzyme A carboxylase of Mycobacterium smegmatis. 44 86

The regulation of acetyl-CoA carboxylase (ACC) by glucose and other fuel molecules has been examined in Fao Reuber hepatoma cells and Syrian hamster insulin tumor (HIT) cells in order to determine whether lipogenic substrates acutely alter ACC activity and to examine the mechanism of such regulation. In Fao cells, preincubated in simple medium without substrates, glucose addition results in a rapid activation of ACC. This effect, mimicked by other fuels such as lactate, is characterized by an increase in enzyme Vmax and a decrease in the activation constant for citrate. Several lines of evidence indicate that this activation of ACC is due to enzyme dephosphorylation, including the kinetic changes observed, the persistence of enzyme activation through ACC isolation, the necessity of inclusion of sodium fluoride/EDTA in the cell lysis buffer for preservation of the glucose-induced change, and the direct demonstration of diminished 32P-labeling of ACC after glucose exposure. Identical effects of glucose are also observed in HIT cells, although the ACC activation is smaller in magnitude and less sensitive than that observed in Fao cells. Other insulin secretagogues such as glutamine, lactate, and isobutylmethylxanthine are also found to activate HIT ACC. Others have suggested that glucose-induced changes in malonyl-CoA in beta-cells may be linked to glucose-induced insulin secretion. However, studies conducted in late passage HIT cells, which fail to secrete insulin in response to glucose stimulation, reveal the same glucose-induced activation seen in early passages, secretion-competent HIT cells, suggesting that glucose-induced ACC activation is not by itself sufficient to provoke insulin secretion. Taken together, these findings indicate that glucose and other fuel molecules can play a major role in the rapid regulation of the fatty acid synthesis pathway. The activation of fatty acid synthesis by substrate-induced ACC dephosphorylation insures ultimate fuel storage of glucose-derived carbon as fatty acid, while substrate-induced increases in the ACC product, malonyl CoA, would serve to simultaneously limit the rate of fatty acid oxidation through its allosteric regulation of carnitine palmitoyltransferase I.
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PMID:Glucose regulation of acetyl-CoA carboxylase in hepatoma and islet cells. 134 95

The effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on acetyl-CoA carboxylase (ACC) activity and synthesis was examined. Male Wistar rats received a single i.p. injection of TCDD (53 micrograms/kg), and nine days later body weight, liver weight, hepatic lipid, ACC activity and mass were determined and compared to pair-fed controls. Body weights of TCDD-treated animals decreased, while liver weights increased resulting in an increase in liver to body weight ratios. ACC activity was decreased by 65%, however sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western analysis using a biotin specific probe revealed that ACC protein levels were not appreciably changed. In addition, there was a large increase in exogenous lipid material in TCDD-treated livers as determined by osmium tetroxide staining. These data suggest that the decrease in ACC activity may be due to direct inhibition of the enzyme by negative allosteric interactions with free fatty acids released from adipose tissue that subsequently accumulate in liver.
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PMID:Alterations of hepatic acetyl-CoA carboxylase by 2,3,7,8-tetrachlorodibenzo-p-dioxin. 168 81


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