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:1.3.1.8 (acyl-CoA dehydrogenase)
785 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The measurement of acyl-CoA dehydrogenase activity is an essential part of the investigation of patients with suspected defects of fatty acid oxidation, and recently the organometallic oxidant ferricenium hexafluorophosphate has been introduced as an electron acceptor for these assays. However, we show that when medium-chain acyl-CoA dehydrogenase activity was measured in cultured skin fibroblasts and platelets from patients with proven defects of this enzyme, there was considerable residual enzyme activity when this electron acceptor was used. The ferricenium assay is not as specific as the anaerobic ETF-linked assay in the biochemical diagnosis of medium-chain acyl-CoA dehydrogenase deficiency in fibroblasts, and therefore is of limited clinical applicability in its present form.
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PMID:Measurement of acyl-CoA dehydrogenase activity in cultured skin fibroblasts and blood platelets. 143 12

The theory of steady-state flux control was applied to characterize the regulation of beta-oxidation flux in uncoupled rat liver mitochondria oxidizing palmitoylcarnitine in the presence of rotenone, malonate and the beta-hydroxybutyrate/acetoacetate redox buffer. By titrations with inhibitors such as antimycin, myxothiazol, azide and 4-pentenoic acid, the flux control coefficients of the b-c1 complex, cytochrome c oxidase and thiolase, were determined experimentally. The flux control coefficients of carnitine palmitoyltransferase II, ETF:CoQ oxidoreductase and beta-hydroxybutyrate dehydrogenase were determined from elasticity coefficients obtained by measuring the flux dependencies of acyl-CoA and acetyl-CoA+CoASH concentrations, the electron transfer flavoprotein redox state, the CoQ redox state and the NAD redox state. It was found that at low flux rates the flux control was distributed mainly between acyl-CoA dehydrogenase and beta-hydroxyacyl-CoA dehydrogenase (Ci = 0.89). At maximum flux rates, carnitine palmitoyltransferase II (Ci = 0.35) and thiolase (Ci = 0.13) contribute additionally to the flux control. Thus, the phenomena of regulation of mitochondrial beta-oxidation can be described as multistep control.
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PMID:Application of the theory of steady-state flux control to mitochondrial beta-oxidation. 166 35

Mammalian electron-transferring flavoproteins have previously been reported to form the red anionic semiquinone on 1-electron reduction. This work describes a new form of electron-transferring flavoprotein (ETFB) from pig kidney which yields the blue neutral semiquinone upon photochemical, dithionite, or enzymatic reduction. ETFB appears in varying amounts as part of an established purification scheme for ETF. Both the normal form of ETF (ETFR) and ETFB show small differences in the spectra of their oxidized flavins, but no detectable differences in molecular weight or subunit composition. The catalytic activities of ETFR and ETFB are comparable when they mediate the transfer of reducing equivalents between medium chain acyl-CoA dehydrogenase and 2,6-dichlorophenolindophenol. ETFB can be converted into a form showing the characteristic red semiquinone of ETFR by full reduction at pH 6.5 or by preparation of the apoprotein and reconstitution with FAD. In contrast, no conditions for the conversion of red to blue forms of ETF have been found. ETFB contains substoichiometric levels of an unusual FAD analogue which yields a pink flavin species on photochemical or dithionite reduction. The evidence presented suggests that ETFB contains a labile factor or protein modification which is irreversibly lost on conversion to ETFR. The possible physiological significance of these data is discussed.
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PMID:A new form of mammalian electron-transferring flavoprotein. 173 21

Studies of the spectral (UV/vis and resonance Raman) and electrochemical properties of the FAD-containing enzyme glutaryl-CoA dehydrogenase (GCD) from Paracoccus denitrificans reveal that the properties of the oxidized enzyme (GCDox) appear to be invariant from those properties known for other acyl-CoA dehydrogenases such as mammalian general acyl-CoA dehydrogenase (GACD) and butyryl-CoA dehydrogenase (BCD) from Megasphaera elsdenii. However, when either free or complexed GCD is reduced, its spectral and electrochemical behavior differs from that of both GACD and BCD. Free GCD does not stabilize any form of one-electron-reduced GCD, but when GCD is complexed to its inhibitor, aceto-acetyl-CoA, the enzyme stabilizes 20% of the blue neutral radical form of FAD (FADH.) upon reduction. Like GACD, when crotonyl-CoA- (CCoA) bound GCD is reduced, the red anionic form of FAD radical (FAD.-) is stabilized, and excess reduction equivalents are necessary to effect full reduction of the complex. A comproportionation reaction is proposed between fully reduced crotonyl-CoA-bound GCD (GCD2e-CCoA) and GCDox-CCoA to partially explain the stabilization of GCD-bound FAD.- by CCoA. When GCD is reduced by its optimal substrate, glutaryl-CoA, a two-electron reduction is observed with concomitant formation of a long-wavelength charge-transfer band. It is proposed that the ETF specific for GCD abstracts one electron from this charge-transfer species and this is followed by the decarboxylation of the oxidized substrate. At pH 6.4, potential values measured for free GCD and GCD bound to acetoacetyl-CoA are -0.085 and -0.129 V, respectively. Experimental evidence is given for a positive shift in the reduction potential of GCD when the enzyme is bound to a 1:1 mixture of butyryl-CoA and CCoA. However, significant GCD hydratase activity is observed, preventing quantitation of the potential shift.
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PMID:Spectral and electrochemical properties of glutaryl-CoA dehydrogenase from Paracoccus denitrificans. 234 Feb 66

A fluorimetric, ETF-linked procedure to determine activities of acyl-CoA dehydrogenase in cultured human fibroblasts is described. The assay readily distinguishes between cell lines deficient in medium-chain acyl-CoA dehydrogenase, long-chain acyl-CoA dehydrogenase, isovaleryl-CoA dehydrogenase, and controls, and may allow for the diagnosis of heterozygous carriers of these disorders. The method has been made feasible with the development of rapid and efficient procedures to isolate ETF, and offers several advantages over procedures that are currently employed.
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PMID:Fluorometric assay of acyl-CoA dehydrogenases in normal and mutant human fibroblasts. 399

Threonine 244 in the alpha subunit of Paracoccus denitrificans transfer flavoprotein (ETF) lies seven residues to the amino terminus of a proposed dinucleotide binding motif for the ADP moiety of the FAD prosthetic group. This residue is highly conserved in the alpha subunits of all known ETFs, and the most frequent pathogenic mutation in human ETF encodes a methionine substitution at the corresponding position, alphaT266. The X-ray crystal structures of human and P. denitrificans ETFs are very similar. The hydroxyl hydrogen and a backbone amide hydrogen of alphaT266 are hydrogen bonded to N(5) and C(4)O of the flavin, respectively, and the corresponding alphaT244 has the same structural role in P. denitrificans ETF. We substituted a methionine for T244 in the alpha subunit of P. denitrificans ETF and expressed the mutant ETF in Escherichia coli. The mutant protein was purified, characterized, and compared with wild type P. denitrificans ETF. The mutation has no significant effect on the global structure of the protein as inferred from visible and near-ultraviolet absorption and circular dichroism spectra, far-ultraviolet circular dichroism spectra, and infrared spectra in 1H2O and 2H2O. Intrinsic fluorescence due to tryptophan of the mutant protein is 60% greater than that of the wild type ETF. This increased tryptophan fluorescence is probably due to a change in the environment of the nearby W239. Tyrosine fluorescence is unchanged in the mutant protein, although two tyrosine residues are close to the site of the mutation. These results indicate that a change in structure is minor and localized. Kinetic constants of the reductive half-reaction of ETF with porcine medium chain acyl-CoA dehydrogenase are unaltered when alphaT244M ETF serves as the substrate; however, the mutant ETF fails to exhibit saturation kinetics when the semiquinone form of the protein is used as the substrate in the disproportionation reaction catalyzed by P. denitrificans electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO). The redox behavior of the mutant ETF was also altered as determined from the equilibrium constant of the disproportionation reaction. The separation of flavin redox potentials between the oxidized/semiquinone couple and semiquinone/hydroquinone couple are -6 mV in the wild type ETF and -27 mV in the mutant ETF. The mutation does not alter the AMP content of the protein, although the extent and fidelity of AMP-dependent, in vitro renaturation of the mutant AMP-free apoETF is reduced by 57% compared to renaturation of wild type apoETF, likely due to the absence of the potential hydrogen bond donor T244.
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PMID:alphaT244M mutation affects the redox, kinetic, and in vitro folding properties of Paracoccus denitrificans electron transfer flavoprotein. 910 14

Acryloyl-CoA reductase from Clostridium propionicum catalyses the irreversible NADH-dependent formation of propionyl-CoA from acryloyl-CoA. Purification yielded a heterohexadecameric yellow-greenish enzyme complex [(alpha2betagamma)4; molecular mass 600 +/- 50 kDa] composed of a propionyl-CoA dehydrogenase (alpha2, 2 x 40 kDa) and an electron-transferring flavoprotein (ETF; beta, 38 kDa; gamma, 29 kDa). A flavin content (90% FAD and 10% FMN) of 2.4 mol per alpha2betagamma subcomplex (149 kDa) was determined. A substrate alternative to acryloyl-CoA (Km = 2 +/- 1 microm; kcat = 4.5 s-1 at 100 microm NADH) is 3-buten-2-one (methyl vinyl ketone; Km = 1800 microm; kcat = 29 s-1 at 300 microm NADH). The enzyme complex exhibits acyl-CoA dehydrogenase activity with propionyl-CoA (Km = 50 microm; kcat = 2.0 s-1) or butyryl-CoA (Km = 100 microm; kcat = 3.5 s-1) as electron donor and 200 microm ferricenium hexafluorophosphate as acceptor. The enzyme also catalysed the oxidation of NADH by iodonitrosotetrazolium chloride (diaphorase activity) or by air, which led to the formation of H2O2 (NADH oxidase activity). The N-terminus of the dimeric propionyl-CoA dehydrogenase subunit is similar to those of butyryl-CoA dehydrogenases from several clostridia and related anaerobes (up to 55% sequence identity). The N-termini of the beta and gamma subunits share 40% and 35% sequence identities with those of the A and B subunits of the ETF from Megasphaera elsdenii, respectively, and up to 60% with those of putative ETFs from other anaerobes. Acryloyl-CoA reductase from C. propionicum has been characterized as a soluble enzyme, with kinetic properties perfectly adapted to the requirements of the organism. The enzyme appears not to be involved in anaerobic respiration with NADH or reduced ferredoxin as electron donors. There is no relationship to the trans-2-enoyl-CoA reductases from various organisms or the recently described acryloyl-CoA reductase activity of propionyl-CoA synthase from Chloroflexus aurantiacus.
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PMID:Acryloyl-CoA reductase from Clostridium propionicum. An enzyme complex of propionyl-CoA dehydrogenase and electron-transferring flavoprotein. 1260 23

Electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO) is a 4Fe4S flavoprotein located in the inner mitochondrial membrane. It catalyzes ubiquinone (UQ) reduction by ETF, linking oxidation of fatty acids and some amino acids to the mitochondrial respiratory chain. Deficiencies in ETF or ETF-QO result in multiple acyl-CoA dehydrogenase deficiency, a human metabolic disease. Crystal structures of ETF-QO with and without bound UQ were determined, and they are essentially identical. The molecule forms a single structural domain. Three functional regions bind FAD, the 4Fe4S cluster, and UQ and are closely packed and share structural elements, resulting in no discrete structural domains. The UQ-binding pocket consists mainly of hydrophobic residues, and UQ binding differs from that of other UQ-binding proteins. ETF-QO is a monotopic integral membrane protein. The putative membrane-binding surface contains an alpha-helix and a beta-hairpin, forming a hydrophobic plateau. The UQ-flavin distance (8.5 A) is shorter than the UQ-cluster distance (18.8 A), and the very similar redox potentials of FAD and the cluster strongly suggest that the flavin, not the cluster, transfers electrons to UQ. Two possible electron transfer paths can be envisioned. First, electrons from the ETF flavin semiquinone may enter the ETF-QO flavin one by one, followed by rapid equilibration with the cluster. Alternatively, electrons may enter via the cluster, followed by equilibration between centers. In both cases, when ETF-QO is reduced to a two-electron reduced state (one electron at each redox center), the enzyme is primed to reduce UQ to ubiquinol via FAD.
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PMID:Structure of electron transfer flavoprotein-ubiquinone oxidoreductase and electron transfer to the mitochondrial ubiquinone pool. 1705 Jun 91

Two horses (a 7-year-old Groninger warmblood gelding and a six-month-old Trakehner mare) with pathologically confirmed rhabdomyolysis were diagnosed as suffering from multiple acyl-CoA dehydrogenase deficiency (MADD). This disorder has not been recognised in animals before. Clinical signs of both horses were a stiff, insecure gait, myoglobinuria, and finally recumbency. Urine, plasma, and muscle tissues were investigated. Analysis of plasma showed hyperglycemia, lactic acidemia, increased activity of muscle enzymes (ASAT, LDH, CK), and impaired kidney function (increased urea and creatinine). The most remarkable findings of organic acids in urine of both horses were increased lactic acid, ethylmalonic acid (EMA), 2-methylsuccinic acid, butyrylglycine (iso)valerylglycine, and hexanoylglycine. EMA was also increased in plasma of both animals. Furthermore, the profile of acylcarnitines in plasma from both animals showed a substantial elevation of C4-, C5-, C6-, C8-, and C5-DC-carnitine. Concentrations of acylcarnitines in urine of both animals revealed increased excretions of C2-, C3-, C4-, C5-, C6-, C5-OH-, C8-, C10:1-, C10-, and C5-DC-carnitine. In addition, concentrations of free carnitine were also increased. Quantitative biochemical measurement of enzyme activities in muscle tissue showed deficiencies of short-chain acyl-CoA dehydrogenase (SCAD), medium-chain acyl-CoA dehydrogenase (MCAD), and isovaleryl-CoA dehydrogenase (IVD) also indicating MADD. Histology revealed extensive rhabdomyolysis with microvesicular lipidosis predominantly in type 1 muscle fibers and mitochondrial damage. However, the ETF and ETF-QO activities were within normal limits indicating the metabolic disorder to be acquired rather than inherited. To our knowledge, these are the first cases of biochemical MADD reported in equine medicine.
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PMID:Equine biochemical multiple acyl-CoA dehydrogenase deficiency (MADD) as a cause of rhabdomyolysis. 1754 May 95

We describe a 22-year-old male who developed severe hypoglycemia and lethargy during an acute illness at 4 months of age and subsequently grew and developed normally. At age 4 years he developed recurrent vomiting with mild hyperammonemia and dehydration requiring frequent hospitalizations. Glutaric aciduria Type II was suspected based upon biochemical findings and managed with cornstarch, carnitine and riboflavin supplements. He did not experience metabolic crises between ages 4-12 years. He experienced recurrent vomiting, mild hyperammonemia, and generalized weakness associated with acute illnesses and growth spurts. At age 18 years, he developed exercise intolerance and proximal muscle weakness leading to the identification of multiple acyl-CoA dehydrogenase and complex II/III deficiencies in both skeletal muscle and liver. Subsequent molecular characterization of the ETFDH gene revealed novel heterozygous mutations, p.G274X:c.820 G > T (exon 7) and p.P534L: c.1601 C > T (exon 12), the latter within the iron sulfur-cluster and predicted to affect ubiquinone reductase activity of ETFDH and the docking of ETF to ETFDH. Our case supports the concept of a structural interaction between ETFDH and other enzyme partners, and suggests that the conformational change upon ETF binding to ETFDH may play a key role in linking ETFDH to II/III super-complex formation.
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PMID:Novel ETF dehydrogenase mutations in a patient with mild glutaric aciduria type II and complex II-III deficiency in liver and muscle. 2108 98


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