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:1.3.99.3 (acyl-CoA dehydrogenase)
1,425 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pig kidney medium-chain acyl-CoA dehydrogenase is specifically alkylated at a methionine residue by treatment with iodoacetate at pH 6.6. This residue corresponds to Met249 in the human medium-chain acyl-CoA dehydrogenase sequence [Kelly, D. P., Kim, J. J., Billadello, J. J., Hainline, B. E., Chu, T. W., & Strauss, A. W. (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 4068-4072]. The S-carboxymethylated dehydrogenase shows a drastically lowered affinity for octanoyl-CoA (from submicromolar to 65 microM), but retains about 23% of the maximal activity of the native enzyme. In addition, alkylation perturbs the internal redox equilibrium: E.FADox.octanoyl-CoA K2 in equilibrium with E.FAD2e.octenoyl-CoA K2 ranges from about 9 for the native enzyme to about 0.2 for the homogeneously modified protein. This effect is not due to a significant change in the redox potential of the free enzyme upon alkylation. Rather, carboxymethylation weakens the preferential binding of enoyl-CoA product to the reduced enzyme (K3) compared to octanoyl-CoA binding to the oxidized dehydrogenase (K1) that is required to pull the substrate thermodynamically uphill. Thus, the ratio of dissociation constants, K1/K3, decreases from about 15,000 for the native enzyme to only 330 upon carboxymethylation of Met249. Binding studies with a variety of acyl-CoA analogues and manipulation of enzyme redox potentials by substitution of the natural prosthetic group by 8-Cl-FAD confirm the thermodynamic effects of alkylation.
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PMID:Reductive half-reaction in medium-chain acyl-CoA dehydrogenase: modulation of internal equilibrium by carboxymethylation of a specific methionine residue. 139 Jun 38

In the enteric bacterium, Escherichia coli, acyl coenzyme A synthetase (fatty acid:CoA ligase (AMP-forming) EC 6.2.1.3) activates exogenous long-chain fatty acids concomitant with their transport across the inner membrane into metabolically active CoA thioesters. These compounds serve as substrates for acyl-CoA dehydrogenase in the first step in the process of beta-oxidation. The acyl-CoA synthetase structural gene, fadD, has been identified on clone 6D1 of the Kohara E. coli gene library and by a process of subcloning and complementation analyses shown to be contained on a 2.2-kilobase NcoI-ClaI fragment of genomic DNA. The polypeptide encoded within this DNA fragment was identified following T7 RNA polymerase-dependent induction and estimated to be M(r) = 62,000 using SDS-polyacrylamide gel electrophoresis. The N-terminal amino acid sequence of acyl-CoA synthetase was determined by automated sequencing to be Met-Lys-Lys-Val-Trp-Leu-Asn-Arg-Tyr-Pro. Sequence analysis of the 2.2-kilobase NcoI-ClaI fragment revealed a single open reading frame encoding these amino acids as the first 10 residues of a protein with a molecular weight of 62,028. The initiation codon for methionine was TTG. Primer extension of total in vivo mRNA from two fadD-specific oligonucleotides defined the transcriptional start at an adenine residue 60 base pairs upstream from the predicted translational start site. Two FadR operator sites of the fadD gene were identified at positions -13 to -29 (OD1) and positions -99 to -115 (OD2) by DNase I footprinting. Comparisons of the predicted amino acid sequence of the E. coli acyl-CoA synthetase to the deduced amino acid sequences of the rat and yeast acyl-CoA synthetases and the firefly luciferase demonstrated that these enzymes shared a significant degree of similarity. Based on the similar reaction mechanisms of these four enzymes, this similarity may define a region required for the same function.
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PMID:Cloning, sequencing, and expression of the fadD gene of Escherichia coli encoding acyl coenzyme A synthetase. 146 45

Complementary DNAs encoding the precursor of human placental short chain acyl-coenzyme A (CoA) dehydrogenase (SCAD) (EC 1.3.99.2) were cloned and sequenced. The cDNA inserts in these clones were 1,852 bases in length combined, and encoded the entire 412-amino acid precursor SCAD (mol wt 44,303). This sequence included the 24-amino acid leader peptide moiety (mol wt 2,576) and 388 amino acids corresponding to the mature protein (mol wt 41,727). The comparison of SCAD and medium chain acyl-CoA dehydrogenase sequences revealed a high degree of homology, suggesting that these enzymes evolved from a common ancestral gene and belong to a gene family. We also studied mutant human SCAD in cultured skin fibroblasts from three patients with hereditary SCAD deficiency. Labeling fibroblast cultures with [35S]-methionine followed by immunoprecipitation with anti-SCAD antibody revealed that a normal size variant SCAD protein was synthesized. In all of the three SCAD-deficient cell lines, the size of variant SCAD mRNA as determined by Northern blotting using one of the normal SCAD cDNA as a probe was also normal, and no difference was observed on Southern blots in the restriction patterns of mutant genomic DNA using EcoRI, TaqI, HincII, and BamHI. These results suggest that the defects in SCAD in these cell lines are caused by a point mutation.
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PMID:Molecular cloning and nucleotide sequence of complementary DNAs encoding human short chain acyl-coenzyme A dehydrogenase and the study of the molecular basis of human short chain acyl-coenzyme A dehydrogenase deficiency. 256 44

4-Thiaacyl-CoA analogues, in which the 4-methylene group is replaced by a thioether sulfur atom, represent new chromophoric substrates of acyl-CoA dehydrogenases and oxidase. The corresponding 4-thia-trans-2-enoyl-CoA products exhibit a strong new absorption band (extinction coefficient 22 mM-1 cm-1) that is red shifted from 312 to 338 nm upon binding to the medium-chain acyl-CoA dehydrogenase. 4-Thiaoctanoyl-CoA reduces the dehydrogenase several-fold slower than octanoyl-CoA, although in turnover it is dehydrogenated 1.5-fold faster. The redox potential of 4-thia analogues is some 30 mV more negative than that of their unsubstituted counterparts. 4-Thia-trans-2-enoyl-CoA derivatives are slowly hydrated by enoyl-CoA hydratase (EC 4.2.1.17) to the corresponding thiohemiacetal which fragments nonenzymatically to 1 equiv each of malonylsemialdehyde-CoA and alkanethiol. This fragmentation reaction might explain the release of methanethiol during the transamination pathway of methionine degradation. 4-Oxaoctanoyl-CoA is a much poorer substrate and kinetic reductant of acyl-CoA dehydrogenase and oxidase than the 4-thia analogue. The corresponding enoyl-CoA product is also fragmented by the hydratase, yielding butanol and malonylsemialdehyde-CoA. Thus, 4-heterosubstituted acyl-CoA derivatives provide new tools for the study of beta-oxidation enzymes.
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PMID:4-Thia-trans-2-alkenoyl-CoA derivatives: properties and enzymatic reactions. 260 83

Our early study of isovaleric acidemia (IVA) indicated that isovaleryl-CoA is dehydrogenated by an enzyme that is specific for isovaleryl-CoA. We subsequently identified and purified isovaleryl-CoA dehydrogenase (IVD) and 2-methyl-branched chain acyl-CoA dehydrogenase, which were previously unknown. We also purified and characterized three previously known acyl-CoA dehydrogenases. Five acyl-CoA dehydrogenases share similar molecular features and reaction mechanisms, indicating a close evolutionary relationship. Using the tritium release assay and [35S]methionine labeling/immunoprecipitation, we showed that IVA is due to a mutation of IVD. We also demonstrated that there are at least 5 distinct forms of mutant IVD, indicating an extensive molecular heterogeneity. Furthermore, we cloned cDNAs encoding IVD and medium-chain acyl-CoA dehydrogenases. The comparison of their complete primary sequences revealed a high degree of homology, indicating that these enzymes belong to a gene family, the acyl-CoA dehydrogenase family.
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PMID:Molecular basis of isovaleric acidemia and medium-chain acyl-CoA dehydrogenase deficiency. 332 38

We prepared monospecific antiserum in rabbits against medium chain acyl-CoA dehydrogenase (MCAD) purified from rat liver and studied the biosynthesis of MCAD in cultured skin fibroblasts from patients with MCAD deficiency using the antibody. Cells were incubated with [35S]methionine. The labeled MCAD was immunoprecipitated using the anti-rat MCAD antiserum and Staphylococcus aureus cells and then analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. We first demonstrated that antirat MCAD antibody crossreacted specifically with human MCAD. In 13 MCAD-deficient cell lines tested, the residual MCAD activity ranged from 5-12% of the mean of normal controls, but the variant MCAD in all of these cells was indistinguishable from the normal human MCAD on the basis of molecular size, indicating that MCAD deficiency in all of these patients is most likely due to point mutation(s) in the MCAD gene.
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PMID:Biosynthesis of variant medium chain acyl-CoA dehydrogenase in cultured fibroblasts from patients with medium chain acyl-CoA dehydrogenase deficiency. 374 57

The flavoprotein pig kidney general acyl-CoA dehydrogenase contains a single catalytically essential methionine residue/FAD which reacts with iodoacetate at pH 6.6. S-Carboxymethylation of this residue generates an inactive enzyme derivative which retains FAD and the tetrameric structure of the native protein. The derivative binds actanoyl-CoA and palmityol-CoA with concomitant perturbation of the flavin chromophore, but the characterisitic spectrum of the reduced enzyme-enoyl-CoA complex is not observed. In addition, octanyol-CoA strongly protects the native enzyme against alkylation with iodoacetate. These results suggest that the methionine residue is within the active center of acyl-CoA dehydrogenase. Carboxymethylation of this residue may disrupt the precise orientation of the substrate required to achieve transfer of reducing equivalents to the flavin. Pig kidney general acyl-CoA dehydrogenase does not contain exposed catalytically essential cysteine residues.
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PMID:An essential methionine in pig kidney general acyl-CoA dehydrogenase. 745 27

We have demonstrated methanethiol production from methionine in isolated rat liver mitochondria and shown how it is affected by other metabolites. The enzymes involved include several transaminases, branched chain 2-oxoacid dehydrogenase, acyl-CoA dehydrogenase, and crotonase. Methanethiol production from methionine in mitochondria isolated from rat liver was increased by 50% after the rats had been given a single injection of glucagon, but was reduced by 25% when the rats had been starved for 24 h. These results indicate the physiological importance of the transaminative pathway of methionine metabolism.
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PMID:The regulation of transaminative flux of methionine in rat liver mitochondria. 797 83

The three-dimensional structure of medium-chain acyl-CoA dehydrogenase from pig mitochondria in the native form and that of a complex of the enzyme and a substrate (product) have been solved and refined by x-ray crystallographic methods at 2.4-A resolution to R factors of 0.172 and 0.173, respectively. The overall polypeptide folding and the quaternary structure of the tetramer are essentially unchanged upon binding of the ligand, octanoyl (octenoyl)-CoA. The ligand binds to the enzyme at the rectus (re) face of the FAD in the crevice between the two alpha-helix domains and the beta-sheet domain of the enzyme. The fatty acyl chain of the thioester substrate is buried inside of the polypeptide and the 3'-AMP moiety is close to the surface of the tetrameric enzyme molecule. The alkyl chain displaces the tightly bound water molecules found in the native enzyme and the carbonyl oxygen of the thioester interacts with the ribityl 2'-hydroxyl group of the FAD and the main-chain carbonyl oxygen of Glu-376. The C alpha--C beta of the fatty acyl moiety lies between the flavin and the gamma-carboxylate of Glu-376, supporting the role of Glu-376 as the base that abstracts the alpha proton in the alpha--beta dehydrogenation reaction catalyzed by the enzyme. Trp-166 and Met-165 are located at the sinister (si) side of the flavin ring at the surface of the enzyme, suggesting that they might be involved in the interactions with electron transferring flavoprotein. Lys-304, the prevalent mutation site found in patients with medium-chain acyl-CoA dehydrogenase deficiency, is located approximately 20 A away from the active site of the enzyme.
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PMID:Crystal structures of medium-chain acyl-CoA dehydrogenase from pig liver mitochondria with and without substrate. 835 49

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


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