• BMB Reports
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• v.28 no.2
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• pp.107-111
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• 1995

In malonate grown Pseudomonas fluorescens, malonate decarboxylase and acetyl-CoA synthetase were induced, whereas in Acinetobacter calcoaceticus malonate decarboxylase, acetate kinase, and phosphate acetyltransferase were induced. In both bacteria malonate decarboxylase was the first, key enzyme catalyzing the decarboxylation of malonate to acetate, and it was localized in the periplasmic space. Acetate thus formed was metabolized to acetyl-CoA directly by acetyl-CoA synthetase in Pseudomonas, and to acetyl-CoA via acetyl phosphate by acetate kinase and phosphate acetyltransferase in Acinetobacter.

• Journal of Nutrition and Health
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• v.35 no.2
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• pp.207-212
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• 2002

Acetyl-CoA carboxylase (ACC) is the enzyme that controls no devo fatty acid biogynthesis, and this enzyme catalyzes the carboxylation pathway of acetyl-CoA to malonyl-CoA. Acetyl-CoA carboxylase gene expression was regulated by nutritional and hormonal status. The present study was performed to identify the regulation mechanism of ACC gene promoter I. The fragments of ACC promoter I -1.2-kb region wert recombined to pGL3-Basic vector with luciferase as a reporter gene. The primary hepatocytes from the rat were used to investigate the hormonal regulation of ACC promoter I activity. ACC PI (-1.2)/Luc plasmid was trtransferred into primary hepatocytes using lipofectin. Activity of luciferase was increased two-fold by 10-9M, three-fold by 10-8M, 10-6M, 3.5-fold by 10-6M, and 4.5-fold by 10-7M insulin treatment, respectively. In the presence of dexamethasone (1 $\mu$M), the effects of insulin increased about 1.5-fold, showing the additional effects of dexamethasone. Moreover, the activity of luciferase increased with insulin+dexamethasone, insulin+T3, dexamethasone+T3, and dexamethasone+insulin+T3 treatment approximately 6-, 4-, 6.5-, and 10-fold, respectively. Therefore it can be postulated that 1) these hormones coordinately regulate acetyl-CoA caroxylase gene expression via regulation of promoter activity, 2) the -1.2-kb region of ACC promoter I may have the response element sequences for insulin, dexamethasone, and T3.

• BMB Reports
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• v.29 no.4
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• pp.277-285
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• 1996

In Pseudomonas fluorescens grown on malonate as sole carbon source, acetyl-CoA synthetase was induced, suggesting that malonate is metabolized through acetate and then acetyl-CoA. Acetyl-CoA synthetase was purified 18.6-fold in 4 steps to apparent homogeneity. The native molecular mass of the enzyme estimated by a native acrylamide gel electrophoresis was 130 kDa. The enzyme was composed of two identical subunits with a molecular mass of 67 kDa. Optimum pH was 70. The acetyl-CoA synthetase showed typical Michaelis-Menten kinetics for the substrates, acetate, ATP and CoA, whose $K_m$ values were calculated to be 33.4, 74.8, and 40.7 mM respectively. Propionate. butyrate and pentanoate were also used as substrates by the enzyme, but the rate of the formation of the CoA derivatives was decreased in the order of the increase in carbon number. The enzyme was inhibited by the group-specific reagents diethylpyro-carbonate, 2,3-butanedione, pyridoxal-5'-phosphate and N-bromosuccinimide. In the presence of substrates the inactivation rate of the enzyme, by all of the group-specific reagents mentioned above decreased, indicating the presence of catalytically essential histidine, arginine, lysine and tryptophan residues at or near the active site. Preincubation of the enzyme with ATP, $Mg^{2+}$ resulted in the increase of its susceptibility to diethylpyrocarbonate, suggesting that ATP, $Mg^{2+}$ may induce a conformational change in the active site exposing the essential histidine residue to diethylpyrocarbonate. The enzyme was acetylated in the presence of acetyl-CoA, indicating that this is one of acyl-enzyme.

• Korean Journal of Exercise Nutrition
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• v.16 no.1
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• pp.1-9
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• 2012

Long chain fatty acids (LCFAs) are transported into cells via plasma transporters, are activated to fatty acyl-CoA by fatty acyl-CoA synthase (ACS), and enter mitochondria via the carnitine system (CPT1/CACT/CPT2). The mitochondrial carnitine system plays an obligatory role in β-oxidation of LCFAs by catalyzing their transport into the mitochondrial matrix. Fatty acyl-CoAs are oxidized via the β-oxidation pathway, which results in the production of acetyl-CoA. The acetyl-CoA can be imported into the tricarboxylic acid (TCA) cycle for oxidation in the mitochondrial matrix or can be used for malonyl-CoA synthesis by acetyl-CoA carboxylase 2 (ACC2) in the cytoplasm. In skeletal muscle, ACC2 catalyzes the carboxylation of acetyl-CoA to form malonyl-CoA, which is a potent endogenous inhibitor of carnitine palmitoyltransferase 1 (CPT1). Thus, ACC2 indirectly inhibits the influx of fatty acids into the mitochondria. Fatty acid metabolism can also be regulated by malonyl-CoA-mediated inhibition of CPT1.

• Journal of Microbiology and Biotechnology
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• v.7 no.4
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• pp.215-222
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• 1997

The regulatory mechanism of the flux of acetyl-CoA in Alcaligenes eutrophus in unbalanced growth conditions was investigated using a PHB-negative mutant and transformants reintroduced PHB-biosynthesis enzymes through the transformation of cloned phbCAB genes. The PHB-negative mutant was defected absolutly in PHB synthase but partially in ${\beta}$-ketothiolase and acetoacetyl-CoA reductase, and excreted substantial amount of pyruvate to culture broth at late growth phase. The excretion was due to the inhibitory effect of acetyl-CoA on the activity of pyruvate dehydrogenase. The cloned phbC and phbCAB genes were transformed to the PHB-negative mutant strain to reintroduce PHB biosythesis enzymes. Pyruvate excretion could be decreased substantially but not completely by transformation of PHB synthase alone, while pyruvate excretion was ceased by transformation of all three PHB biosynthesis enzymes. To identify the most critical PHB biosynthesis enzyme influencing on the flux of acetyl-CoA, the effect of the variation of PHB biosynthesis enzymes on pyruvate dehydrogenase was investigated. ${\beta}$-Ketothiolase influenced the activity of pyruvate dehydrogenase more sensitively than PHB synthase. ${\beta}$-Ketothiolase, the first step enzyme of PHB biosynthesis that condense acetyl-CoA to acetoacetyl-CoA, seems to be the major enzyme determining the flux of acetyl-CoA to PHB biosynthesis or TCA cycle, and the rate of PHB biosynthesis in A. eutrophus.

• Tuberculosis and Respiratory Diseases
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• v.80 no.3
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• pp.255-264
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• 2017

Background:N-acetyl transferase (NAT) inactivates the pro-drug isoniazid (INH) to N-acetyl INH through a process of acetylation, and confers low-level resistance to INH in Mycobacterium tuberculosis (MTB). Similar to NAT of MTB, NAT2 in humans performs the same function of acetylation. Rapid acetylators, may not respond to INH treatment efficiently, and could be a potential risk factor, for the development of INH resistance in humans. Methods: To understand the contribution of NAT of MTB and NAT2 of humans in developing INH resistance using in silico approaches, in this study, the wild type (WT) and mutant (MT)-NATs of MTB, and humans, were modeled and docked, with substrates and product (acetyl CoA, INH, and acetyl INH). The MT models were built, using templates 4BGF of MTB, and 2PFR of humans. Results: On the basis of docking results of MTB-NAT, it can be suggested that in comparison to the WT, binding affinity of MT-G207R, was found to be lower with acetyl CoA, and higher with acetyl-INH and INH. In case of MT-NAT2 from humans, the pattern of score with respect to acetyl CoA and acetyl-INH, was similar to MT-NAT of MTB, but revealed a decrease in INH score. Conclusion: In MTB, MT-NAT revealed high affinity towards acetyl-INH, which can be interpreted as increased formation of acetyl-INH, and therefore, may lead to INH resistance through inactivation of INH. Similarly, in MT-NAT2 (rapid acetylators), acetylation occurs rapidly, serving as a possible risk factor for developing INH resistance in humans.

• Analytical Science and Technology
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• v.8 no.4
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• pp.869-876
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• 1995

The active sites of the nickel and iron-containing enzyme, carbon monoxide dehydrogenase (CODH) from clostridium thermoaceticum were investigated using Electron Paramagnetic Resonance (EPR) technique. CODH exhibits several spectral features called NiFeC, $g_{ave}=1.82$, $g_{ave}=1.86$. FCII signals which are originated from different clusters in this enzyme. CODH is know to catalyze two different kinds of reactions - acetyl-CoA synthesis and CO oxidation. The acetyl-CoA synthesis activity can be followed by monitoring CO/acetyl-CoA exchange. The addition of 1,10-phenanthroline (phen) to CODH selectively destroyed the CO/acetyl-CoA exchange activity and eliminated the NiFeC signal completely. CO oxidation activity and other EPR signals were unaffected. Such behavior demonstrates that CODH has two distinct active sites and that the NiFe complex is only responsible for the CO/acctyl-CoA exchange activity. Phen caused the removal of only 30% of Ni in the NiFe complex ($0.3Ni/{\alpha}{\beta}$) as shown by the quantitative metal analysis. The phen-treated CODH could be reactivated fully by incubation In $Ni^{2+}$ solution. Radioactive $^{63}Ni^{2+}$ was used to quantitate the amount of the $Ni^{2+}$ incorporated into phen-treated enzyme and showed that the amount was the same as the removed by the phen treatment. i.e. $0.3Ni/{\alpha}{\beta}$. This indicates that only 30% of NiFe complexes are labile and responsible for the CO/acctyl-CoA exchange activity, the other 70% are non-labile and have no exchange activity. This is the first clear evidence that the NiFe complex is heterogencous and labile and non-labile Ni sites arc interacting differently with substrates and chelating agents like phen.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.565-568
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• 2013

Acetyl-CoA carboxylases (ACCs) play critical roles in fatty acid synthesis and oxidation by the catalytic activity of the carboxylation of acetyl-CoA to malonyl-CoA. It is known that ACCs are inactivated through reversible phosphorylation by AMP-activated protein kinase (AMPK) and allosterically activated by citrate. Here, we determined the crystal structures of biotin carboxylase (BC) domain of human ACC2 phosphorylated by AMPK in the presence of citrate in order to elucidate the activation mechanism by citrate. This structure shows that phosphorylated Ser222 is released from the dimer interface, and thereby facilitating the dimerization or oligomerization of the BC domain allosterically. This structural explanation is coincident with the experimental result that the phosphorylated Ser222 was dephosphorylated more easily by protein phosphatase 2A (PP2A) as the citrate concentration increases.

• Journal of IKEEE
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• v.21 no.3
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• pp.309-319
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• 2017

The research investigates the inhibition of fatty acid biosynthesis of the human Acetyl-CoA Carboxylase enzyme by the aromatic-structure inhibitors (also known as ligands) containing variables of substituents, contributing an important role in the treatment of fatty-acid metabolic syndrome expressed by the group of cardiovascular risk factors increasing the incidence of coronary heart disease and type-2 diabetes. The effective interoperability between ligand and enzyme is characterized by a 50% concentration of enzyme inhibitor ($IC_{50}$) which was determined by experiment, and the factor of geometry structure of the ligands which are modeled by quantum mechanical methods using HyperChem 8.0.10 and Gaussian 09W softwares, combining with the calculation of quantum chemical and chemico-physical structural parameters using HyperChem 8.0.10 and Padel Descriptor 2.21 softwares. The result data are processed with the combination of classical statistical methods and modern bioinformatics methods using the statistical softwares of Department of Pharmaceutical Technology - Jadavpur University - India and R v3.3.1 software in order to accomplish a model of the quantitative structure - activity relationship between aromatic-structure ligands inhibiting fatty acid biosynthesis of the human Acetyl-CoA Carboxylase.

• Microbiology and Biotechnology Letters
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• v.14 no.2
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• pp.181-186
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• 1986

A defective lambda transducing phase carrying acetyl CoA carboxylase gene (fabE) from Escherichia coli chromosome (72 min on the current linkage map) has been isolated. A restriction map of the chromosomal region from defective transducing phage was established by digestion with combination of the restriction enzymes. No cleavage site for the enzyme EcoRI was found in this region. Restriction fragments were cloned from defective transducing phage into high copy number plasmid vector pACYC184 to generate hybrid plasmids which were capable of complementation of fabE temperature sensitive mutation. We show here that the fabE gene is located on a 3.4 megadalton Bam HI-SalI fragment with a HindIII site, which lies within the 7.4 megadalton BglIIfragment, by complementation analysis.