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Insulin promotes an association between acetyl CoA carboxylase and acetyl CoA carboxylase phosphatase. The association between rat epididymal fat tissue carboxylase and the phosphatase occurs in both a tissue culture system and in vivo and is accompanied by an increase in acetyl CoA carboxylase activity. 相似文献
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Essential arginine residues in the active sites of propionyl CoA carboxylase and beta-methylcrotonyl CoA carboxylase 总被引:1,自引:0,他引:1
At least one arginine residue is essential for substrate binding in or near the active sites of propionyl CoA carboxylase (PCC) and beta-methylcrotonyl CoA carboxylase (beta MCC) in cultured human fibroblasts. This conclusion is based on studies of enzyme inhibition by phenylglyoxal, a reagent which specifically modifies arginine residues. Human fibroblast PCC both in extracts and in a 20-fold purified preparation was nearly completely protected from phenylglyoxal inhibition following incubation with propionyl CoA or ATP. It appears that a phosphate group from either ATP or the CoA moiety of propionyl CoA reacts with the essential arginine residue(s). beta MCC which was similarly inhibited by phenylglyoxal was protected by beta-methylcrotonyl CoA and ATP. Thus phenylglyoxal may be used to label specific arginine residues within the active sites of previously sequenced carboxylases. 相似文献
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Two biotin-containing polypeptides of molecular weights 140,000 and 22,000 have been identified by gel electrophoresis in a sodium dodecyl sulfate-denatured extract of cells of a thermophilic Bacillus. These polypeptides can be separated from each other by either gel filtration through Sepharose 6B or affinity chromatography on a Sepharose-avidin column. The larger polypeptide is renatured under appropriate conditions to yield enzymically active pyruvate carboxylase. Enzyme reconstitution experiments show that the smaller polypeptide is a component of acetyl CoA carboxylase. The biotin subunits of these two carboxylases are thus distinct from, and dissimilar to, each other. The demonstration that a pyruvate carboxylase-deficient mutant of the Bacillus contains the smaller, but not the larger, polypeptide corroborates this conclusion. 相似文献
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Cloning of acetyl CoA carboxylase cDNA and the effects of spirodiclofen on the expression of acetyl CoA carboxylase mRNA in Panonychus citri
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Shijiang Yu Huixia Tian Juan Yang Lili Ding Fei Chen Xiaojiao Li Jiansu Yue Haoqiang Liu Chun Ran 《Entomologia Experimentalis et Applicata》2015,156(1):52-58
The citrus red mite, Panonychus citri (McGregor) (Acari: Tetranychidae), is an important pest worldwide. Previous studies showed that acetyl CoA carboxylase (ACCase) may be a critical target of spirodiclofen, a recently introduced insecticide. Therefore, we cloned the PcACCase gene and obtained a full‐length cDNA (Genbank accession number KJ675439 ). The open reading frame was 6 972 bp, coding for 2 323 amino acids. The PcACCase protein had a theoretical molecular weight of 262.82 kDa and an isoelectric point of 6.31, and it contained six conserved domains and one low‐complexity region. Quantitative real‐time PCR showed that spirodiclofen can up‐regulate the expression levels of ACCase mRNA during all four developmental stages. 相似文献
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Inhibition of rat liver acetyl CoA carboxylase by chloride 总被引:2,自引:0,他引:2
The activity of acetyl CoA carboxylase in both crude and purified rat liver preparations was reduced in the presence of sodium or potassium chloride and increased in the presence of potassium acetate. The chloride inhibition was not competitive with bicarbonate. The use of Trischloride buffer did not alter the apparent pH optimum of the enzyme when compared with Tris-acetate buffer. 相似文献
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R D Tkachuck H J Saz P P Weinstein K Finnegan J F Mueller 《The Journal of parasitology》1977,63(5):769-774
Both spargana and adult forms of Spirometra mansonoides were shown to accumulate lactate, succinate, acetate, and propionate upon in vitro incubation. Adults differed markedly from the spargana in that quantitatively the most significant products of the former were acetate and propionate while the latter formed primarily acetate and lactate. The adults accumulated approximately 32 times more propionate than the spargana per gram of tissue. In accord with this propionate formation, propionyl CoA carboxylase and methylmalonyl CoA mutase have been found to be present in both stages of the parasite. As might be predicted, however, the activities of the carboxylase and mutase were 100-fold and 10-fold higher, respectively, in the adults as compared to the larvae. A possible physiological relationship between propionate formation and energy generation is suggested. Accordingly, inorganic 32P was incorporated into ATP upon incubation of methylmalonyl CoA with a homogenate obtained from adult S. mansonoides. Since methylmalonyl CoA mutase requires vitamin B12 coenzyme, a relationship between vitamin B12 content and propionate formation in helminths is suggested. 相似文献
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Acetyl CoA carboxylase in the isolated epididymal fat tissue is activated by insulin and inactivated by epinephrine and dibutyryl cAMP. Insulin activation of the enzyme occurs in the presence of inhibitors of protein synthesis and can be observed as early as 15 min. A time dependent inactivation of the enzyme occurs in the presence of ATP and Mg++. 相似文献
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S Numa E Ringelmann B Riedel 《Biochemical and biophysical research communications》1966,22(5):750-757
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Barry Wolf 《Experimental cell research》1980,125(2):502-507
The extent of genetic complementation in polyethylene glycol-induced heterokaryons of propionyl CoA carboxylase deficient fibroblast lines was determined by comparing enzyme activity changes over time in pairwise fusions of the three major complementation groups, bio, pcc A and pcc C, with the activity changes in similarly mixed but unfused cultures. Maximum complementation between bio and pcc. A or pcc C lines was attained within 24 h after fusion and was not inhibited by cycloheximide. In contrast, the complementation between pcc A and pcc C lines only attained 50% of the maximum restored carboxylase activity by 24–36 h and the increase was 93% inhibited by cycloheximide. Maximum restoration of activity was not achieved until 72–96 h after fusion. Removal of cycloheximide at 24 h permitted complementation to take place. Our studies suggest that intergenic complementation between the bio and pcc A or pcc C lines is due to the contribution within the heterokaryon of normal enzymes from each of the respective lines, resulting in almost immediate, protein synthesis-independent, partial restoration of carboxylase activity. Complementation between pcc A and pcc C lines also appears to be intergenic but probably results from the de novo synthesis of normal subunits and protomers which assemble into normal or stabilized propionyl CoA carboxylase molecules with restored enzyme activity. 相似文献
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Acetyl CoA carboxylase was purified from liver of fasted-refed rats to near homogeneity, based on electrophoretic analysis and biotin content. These preparations contained an endogenous protein kinase that catalyzed the transfer of radioactive phosphate from [gamma-32P]ATP to acetyl CoA carboxylase, accompanied by a decrease in acetyl CoA carboxylase activity. Phosphate incorporated into acetyl CoA carboxylase was removed when the preparation was incubated with partially purified phosphorylase phosphatase catalytic subunit with regain of enzymatic activity. This endogenous protein kinase was shown not to be affected by either cyclic-AMP-dependent protein kinase inhibitor, EGTA, or trifluoperazine. The addition of either cyclic-AMP or purified cyclic-AMP-dependent protein kinase catalytic subunit to the purified acetyl CoA carboxylase preparation increased protein phosphorylation but had no further effect on acetyl CoA carboxylase activity. Purified acetyl CoA carboxylase was shown to act as an ATPase during the phosphorylation reaction. 相似文献
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In this review we examine the effects of the allosteric activator, acetyl CoA on both the structure and catalytic activities of pyruvate carboxylase. We describe how the binding of acetyl CoA produces gross changes to the quaternary and tertiary structures of the enzyme that are visible in the electron microscope. These changes serve to stabilize the tetrameric structure of the enzyme. The main locus of activation of the enzyme by acetyl CoA is the biotin carboxylation domain of the enzyme where ATP-cleavage and carboxylation of the biotin prosthetic group occur. As well as enhancing reaction rates, acetyl CoA also enhances the binding of some substrates, especially HCO3-, and there is also a complex interaction with the binding of the cofactor Mg2. The activation of pyruvate carboxylase by acetyl CoA is generally a cooperative processes, although there is a large degree of variability in the degree of cooperativity exhibited by the enzyme from different organisms. The X-ray crystallographic holoenzyme structures of pyruvate carboxylases from Rhizobium etli and Staphylococcus aureus have shown the allosteric acetyl CoA binding domain to be located at the interfaces of the biotin carboxylation and carboxyl transfer and the carboxyl transfer and biotin carboxyl carrier protein domains. 相似文献
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Wheat germ acetyl CoA carboxylase requires certain alkali cations to exhibit maximal activity. Maximal activation results when 60 mM K+ or Rb+ are included in the assay mixture, whereas only marginal activation occurs in the presence of similar concentrations of Li++ and Na++. Cs++ activates, but less effectively than K+ or Rb+. Since it is also possible to activate the enzyme maximally using 20 mM potassium isocitrate, but not 20 mM sodium isocitrate, activation of the wheat germ enzyme is due to a cation effect and not to citrate anion. 相似文献
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Alan R. Saltiel Adam Doble Steven Jacobs Pedro Cuatrecasas 《Biochemical and biophysical research communications》1983,110(3):789-795
Incubation of rat liver plasma membranes with insulin enhances the production of small molecular weight substances which regulate the activity of liver acetyl CoA carboxylase. While low concentrations of insulin cause the release of a carboxylase stimulator from membranes, concentrations greater than 10?9 M generate less stimulating activity. This biphasic concentration curve for insulin can be resolved by differential alcohol extraction into two fractions which have antagonistic activity. The production of both substances is enhanced by insulin. Chemical and chromatographic evidence suggest that these substances are identical to the previously described “mediators” which regulate both pyruvate dehydrogenase and adenylate cyclase activities. 相似文献
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