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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)
Medium-chain acyl-CoA dehydrogenase
reduced with octanoyl-CoA is reoxidized in two one-electron steps by two molecules of the physiological oxidant, electron transferring flavoprotein (ETF). The organometallic oxidant ferricenium hexafluorophosphate (Fc+PF6-) is an excellent alternative oxidant of the dehydrogenase and mimics a number of the features shown by ETF. Reoxidation of octanoyl-CoA-reduced enzyme (200 microM Fc+PF6- in 100 mM Hepes buffer, pH 7.6, 1 degree C) occurs in two one-electron steps with pseudo-first-order rate constants of 40 s-1 and about 200 s-1 for k1 and k2, respectively. The reaction is comparatively insensitive to ionic strength, and evidence of rate saturation is encountered at high ferricenium ion concentration. As observed with ETF, the free two-electron-reduced dehydrogenase is a much poorer kinetic reductant of Fc+PF6-, with rate constants of 3 s-1 and 0.3 s-1 (for k1 and k2, respectively) using 200 microM Fc+PF6-. In addition to the enoyl-CoA product formed during the dehydrogenation of octanoyl-CoA, binding a number of redox-inert acyl-CoA analogues (notably 3-thia- and 3-oxaoctanoyl-CoA) significantly accelerates electron transfer from the dehydrogenase to Fc+PF6-. Those ligands most effective at accelerating electron transfer favor deprotonation of reduced flavin species in the
acyl-CoA dehydrogenase
. Thus this rate enhancement may reflect the anticipated kinetic superiority of anionic flavin forms as reductants in outer-sphere electron-transfer processes. Evidence consistent with the presence of two distinct loci for redox communication with the bound flavin in the
acyl-CoA dehydrogenase
is presented.
...
PMID:Alternate electron acceptors for medium-chain acyl-CoA dehydrogenase: use of ferricenium salts. 227 71
Medium-chain acyl-CoA dehydrogenase
deficiency is a recently described inborn error of metabolism characterized by episodes of coma and hypoketotic hypoglycaemia in response to prolonged fasting. Secondary carnitine deficiency has been documented in these patients as well as the excretion in the urine of medium-chain-length acyl carnitine esters, such as octanoylcarnitine. Based on the potential toxicity of medium-chain fatty acid metabolites and the beneficial responses of patients with other inborn errors of metabolism and secondary carnitine deficiency, oral carnitine has been proposed as treatment for children with
medium-chain acyl-CoA dehydrogenase
deficiency. We report the results of carefully monitored fasting challenges of an infant with this deficiency both before and after 3 months of oral carnitine therapy. Carnitine supplementation failed to prevent lethargy, vomiting, hypoglycaemia and accumulation of free fatty acids in response to fasting despite normalization of plasma carnitine levels and a marked increase in urinary excretion of acyl-carnitine esters. Potentially toxic medium-chain fatty acids accumulated in the plasma in spite of therapy. Based on this study of one patient, we stress that avoidance of fasting and prompt institution of glucose supplementation in situations when oral intake is interrupted remain the mainstays of therapy for
medium-chain acyl-CoA dehydrogenase
deficient patients.
...
PMID:Medium-chain acyl-CoA dehydrogenase deficiency: metabolic effects and therapeutic efficacy of long-term L-carnitine supplementation. 250 71
Medium-chain acyl-CoA dehydrogenase
(MCAD; acyl-CoA: (acceptor) 2,3-oxidoreductase,
EC 1.3.99.3
) is one of three similar enzymes that catalyze the initial step of fatty acid beta-oxidation. Definition of the primary structure of MCAD and the tissue distribution of its mRNA is of biochemical and clinical importance because of the recent recognition of inherited MCAD deficiency in humans. The MCAD mRNA nucleotide sequence was determined from two overlapping cDNA clones isolated from human liver and placental cDNA libraries, respectively. The MCAD mRNA includes a 1263-base-pair coding region and a 738-base-pair 3'-nontranslated region. A partial amino acid sequence (137 residues) determined on peptides derived from MCAD purified from porcine liver confirmed the identity of the cDNA clone. Comparison of the amino acid sequence predicted from the human MCAD cDNA with the partial protein sequence of the porcine MCAD revealed a high degree (88%) of interspecies sequence identity. RNA blot analysis shows that MCAD mRNA is expressed in a variety of rat (2.2 kilobases) and human (2.4 kilobases) tissues. Blot hybridization of RNA prepared from cultured skin fibroblasts from a patient with MCAD deficiency disclosed that mRNA was present and of similar size to MCAD mRNA derived from control fibroblasts. The isolation and characterization of MCAD cDNA is an important step in the definition of the defect underlying MCAD deficiency and in understanding its metabolic consequences.
...
PMID:Nucleotide sequence of medium-chain acyl-CoA dehydrogenase mRNA and its expression in enzyme-deficient human tissue. 303 65
Urinary organic acid profiles in patients with inherited defects of fatty acid metabolism and ketogenesis are described.
Medium-chain acyl-CoA dehydrogenase
, short-chain acyl-CoA dehydrogenase, multiple
acyl-CoA dehydrogenase
, and 3-hydroxy-3-methyl-glutaryl-CoA lyase deficiencies can be recognized at the metabolite level. Data on
long-chain acyl-CoA dehydrogenase
and systemic carnitine deficiencies are scarce. In the latter disorders, dicarboxylic aciduria is rather nonspecific and points to a modest omega-oxidation of long chain fatty acids.
...
PMID:Chemical diagnosis of inherited defects of fatty acid metabolism and ketogenesis. 332 28
Medium-chain acyl-CoA dehydrogenase
deficiency is the most common genetic defect of hepatic fatty acid oxidation. Clinical signs are somnolence and lethargy potentially leading to coma. Death occurs during the first attack in about 20% of cases, suggesting sudden infant death syndrome. A point mutation (adenine to guanine at position 985) in exon 11 of the
medium-chain acyl-CoA dehydrogenase
gene accounts for 90% of
medium-chain acyl-CoA dehydrogenase
deficiency-causing alleles. Such a high prevalence of a single mutation makes it possible to estimate the incidence of
medium-chain acyl-CoA dehydrogenase
deficiency in the general population and in sudden infant death syndrome. The study was performed by polymerase chain reaction amplification from blood spots on filter paper in 2000 randomly selected newborns (group I) and in 225 infants dead from sudden infant death syndrome (group II). Among 2000 newborns, 17 were found to be heterozygote for the G985 mutation. In group II, one child was found with a single copy of the G985 mutation. So, the estimated frequency of the G985 mutation in the general population was 1/118 and the incidence of
medium-chain acyl-CoA dehydrogenase
deficiency was calculated as around 1/45,000 in Normandy.
...
PMID:The A985 to G mutation of the medium-chain acyl-CoA dehydrogenase gene and sudden infant death syndrome in Normandy. 864 38
In a 14-year-old Japanese girl, manifested recurrent myalgia with elevated serum creatine kinase after moderate exercise became evident, and she was diagnosed as having a myopathic form of very-long chain acyl-CoA dehydrogenase deficiency. Her first clinical symptom of the disease was evident when she was 6 y of age. She had never had hypoglycemic attacks, and hepatomegaly and cardiomyopathy were absent. The diagnosis was suspected on the basis of the urinary organic acid profile after a 36-h fast, long-chain fatty acid-loading test, and the blood acylcarnitine profile.
Acyl-CoA dehydrogenase
activity with palmitoyl-CoA as a substrate was severely decreased in her fibroblasts, and the amount of very-long chain acyl-CoA dehydrogenase protein was reduced. She was a compound heterozygote of A416T from her father and R450H from her mother. Transient expression of mutant A416T cDNA retained a significant residual
acyl-CoA dehydrogenase
activity of 10% and 20% normal at 37 degrees C and 30 degrees C, respectively. Specific activity of A416T mutant protein was calculated to be one fifth that of control. In the case of R450H mutant expression, a low residual
acyl-CoA dehydrogenase
activity of 5% normal was detected at 30 degrees C although significant activity was absent at 37 degrees C. The R450H protein was not detected at 37 degrees C but was clearly detected at one fourth the normal amount at 30 degrees C. These results indicate that both mutations were temperature-sensitive mild mutations, the result being the mildest phenotype of very-long chain acyl-CoA dehydrogenase deficiency.
...
PMID:Myopathic form of very-long chain acyl-coa dehydrogenase deficiency: evidence for temperature-sensitive mild mutations in both mutant alleles in a Japanese girl. 1115 18
Acyl-CoA dehydrogenase
activity has been measured in homogenates of post-imbibition to 14-day-old hydroponically grown pea seeds at daily intervals, using C(4), C(12) and C(16) acyl-CoA substrates. The activity peaks of the different chain-length acyl-CoA dehydrogenases did not transpose at all points and the ratios of the chain-length activities were not constant. It therefore has to be concluded that more than one dehydrogenase is present in pea mitochondria. There was a post-imbibition initial surge of activity with short- and mid-chain-length substrates. The C(16)-handling enzyme first peaked at 3-4 days, which coincided with the onset of plumule unfurling and greening. Further peaks were observed with all three substrates, coinciding with secondary root formation and leaf enlargement and later with cotyledon degeneration. Overall activity showed that the
long-chain acyl-CoA dehydrogenase
was much more active than the short-chain acyl-CoA dehydrogenase.
...
PMID:Acyl-CoA dehydrogenase activity in pea cotyledon tissue during germination and initial growth. 1117 Nov 98
Tandem mass spectrometry is an analytical method which is being implemented for neonatal screening. The method can determine the content of amino acids and acylcarnitines in neonatal screening samples in one integrated analysis. This allows detection of more than 20 inherited disorders of amino acid, fatty acid and organic acid metabolism. The aggregate incidence of these disorders is in the order of 1:4000. The principal disease which is detectable is
medium-chain acyl-CoA dehydrogenase
deficiency, which has an incidence of 1:10,000-1:20,000 in Northern Europe.
Medium-chain acyl-CoA dehydrogenase
deficiency puts the affected at risk of life-threatening metabolic crises, which are preventable if the condition has been diagnosed. Hence, the prognosis is excellent. The central theme for therapeutic management of
medium-chain acyl-CoA dehydrogenase
deficiency is carbohydrate supplementation, especially in situations of intercurrent illness. Tandem mass spectrometry screening will also enhance the present screening for phenylketonuria which employs a bacterial assay: the screening sample can be obtained 48-72 hours post partum, the false-positive rate will be reduced, and there will be no interference with antibiotics. Tandem mass spectrometry is being used in state-mandated screening panels in a few places and is being tested in pilot studies in many other places. A national prospective pilot project was launched on February 1, 2002 in Denmark. The project includes tandem mass spectrometry screening for galactosemia. In addition to neonatal screening, tandem mass spectrometry can be used for investigation of metabolic diseases, sudden unexpected death of infancy and shaken baby syndrome. Critical appraisal of tandem mass spectrometry will lead to improved health for infants affected by rare inherited disorders of metabolism.
...
PMID:[Screening of newborns for inborn errors of metabolism by tandem mass spectrometry]. 1252 3
Acyl-CoA dehydrogenase
gene (yafH) of Escherichia coli was expressed together with polyhydroxyalkanoate synthase gene (phaC(Ac)) and (R)-enoyl-CoA hydratase gene (phaJ(Ac)) from Aeromonas caviae. The expression plasmids were introduced into E. coli JM109, DH5 alpha and XL1-blue, respectively. Compared with the strains harboring only phaC(Ac) and phaJ(Ac), all recombinant E. coli strains harboring yafH, phaC(Ac) and phaJ(Ac) accumulated at least four times more poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx). Cell dry weights produced by all recombinants containing yafH were also considerably higher than that without yafH. The addition of acrylic acid which serves as inhibitor for beta-oxidation and may lead to more precursor supply for PHA synthesis did not result in improved PHBHHx production compared with that of the overexpression of yafH. It appeared that the overexpression of
acyl-CoA dehydrogenase
gene (yafH) enhanced the supply of enoyl-CoA which is the substrate of (R)-enoyl-CoA hydratase. With the enhanced precursor supply, the recombinants accumulated more PHBHHx.
...
PMID:Enhanced production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) via manipulating the fatty acid beta-oxidation pathway in E. coli. 1269 16
The acyl-CoA dehydrogenases are a family of multimeric flavoenzymes that catalyze the alpha,beta -dehydrogenation of acyl-CoA esters in fatty acid beta -oxidation and amino acid catabolism. Genetic defects have been identified in most of the acyl-CoA dehydrogenases in humans.
Acyl-CoA dehydrogenase
9 (ACAD9) is a recently identified
acyl-CoA dehydrogenase
that demonstrates maximum activity with unsaturated long-chain acyl-CoAs. We now report three cases of ACAD9 deficiency. Patient 1 was a 14-year-old, previously healthy boy who died of a Reye-like episode and cerebellar stroke triggered by a mild viral illness and ingestion of aspirin. Patient 2 was a 10-year-old girl who first presented at age 4 mo with recurrent episodes of acute liver dysfunction and hypoglycemia, with otherwise minor illnesses. Patient 3 was a 4.5-year-old girl who died of cardiomyopathy and whose sibling also died of cardiomyopathy at age 21 mo. Mild chronic neurologic dysfunction was reported in all three patients. Defects in ACAD9 mRNA were identified in the first two patients, and all patients manifested marked defects in ACAD9 protein. Despite a significant overlap of substrate specificity, it appears that ACAD9 and very-long-chain acyl-CoA dehydrogenase are unable to compensate for each other in patients with either deficiency. Studies of the tissue distribution and gene regulation of ACAD9 and very-long-chain acyl-CoA dehydrogenase identify the presence of two independently regulated functional pathways for long-chain fat metabolism, indicating that these two enzymes are likely to be involved in different physiological functions.
...
PMID:A new genetic disorder in mitochondrial fatty acid beta-oxidation: ACAD9 deficiency. 1756 66
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