Publications

• The existence of an inner-membrane-bound, long acyl-chain-specific 3-hydroxyacyl-CoA dehydrogenase in mammalian mitochondria.

  El-Fakhri M., Middleton B.

  L-3-Hydroxyacyl-CoA dehydrogenase was measured in mammalian tissues with long-chain (C16) and short-chain (C4) 3-ketoacyl-CoA substrates. The majority of the activity was mitochondrial. Activity with C16 substrate was enriched in the inner membrane fraction while the matrix showed enrichment of ac ... >> More

  L-3-Hydroxyacyl-CoA dehydrogenase was measured in mammalian tissues with long-chain (C16) and short-chain (C4) 3-ketoacyl-CoA substrates. The majority of the activity was mitochondrial. Activity with C16 substrate was enriched in the inner membrane fraction while the matrix showed enrichment of activity with C4 substrate. Gel-filtration in the presence of nonionic and ionic detergents separated two peaks of activity with C16 substrate from liver, heart, kidney and brown adipose tissue mitochondria. The highest molecular weight activity was associated with membrane fragments and accounted for 18-32% of the total activity with C16 substrate. This enzyme showed preference for long-chain substrate, the C16/C4 activity ratio being 6-15 for the different mitochondria studied. The other enzyme had a molecular weight of 71 000 and showed highest activity with C4 substrate (C16/C4 activity ratio of 0.2). The substrate specificity of the membrane-associated enzyme was not altered by extraction with detergent or lipid solvents. The membrane-associated enzyme could be partially purified by treatment with high concentrations of KCl and EDTA, when it showed a molecular weight of 186 000 while retaining its high C16/C4 activity ratio. Protease treatment caused loss of C4 activity from the high-molecular-weight enzyme without affecting its C16 activity. We conclude that an inner membrane-associated, long-chain-specific 3-ketoacyl-CoA dehydrogenase coexists in mitochondria with the better-documented matrix enzyme which shows preference for shorter-chain-length substrates. << Less

  Biochim Biophys Acta 713:270-279(1982) [PubMed] [EuropePMC]

• The molecular basis of pediatric long chain 3-hydroxyacyl-CoA dehydrogenase deficiency associated with maternal acute fatty liver of pregnancy.

  Sims H.F., Brackett J.C., Powell C.K., Treem W.R., Hale D.E., Bennett M.J., Gibson B., Shapiro S., Strauss A.W.

  Mitochondrial long chain fatty acid beta-oxidation provides the major source of energy in the heart. Deficiencies of human beta-oxidation enzymes produce sudden, unexplained death in childhood, acute hepatic encephalopathy, skeletal myopathy, or cardiomyopathy. Long chain 3-hydroxyacyl-CoA dehydro ... >> More

  Mitochondrial long chain fatty acid beta-oxidation provides the major source of energy in the heart. Deficiencies of human beta-oxidation enzymes produce sudden, unexplained death in childhood, acute hepatic encephalopathy, skeletal myopathy, or cardiomyopathy. Long chain 3-hydroxyacyl-CoA dehydrogenase [LCHAD; long-chain-(S)-3-hydroxyacyl-CoA:NAD+ oxidoreductase, EC 1.1.1.211] catalyzes the third step in beta-oxidation, and this activity is present on the C-terminal portion of the alpha subunit of mitochondrial trifunctional protein. We used single-stranded conformation variance analysis of the exons of the human LCHAD (alpha subunit) gene to determine the molecular basis of LCHAD deficiency in three families with children presenting with sudden unexplained death or hypoglycemia and abnormal liver enzymes (Reye-like syndrome). In all families, the mothers had acute fatty liver and associated sever complications during pregnancies with the affected infants. The analysis in two affected children revealed a G to C mutation at position 1528 (G1528C) of the alpha subunit of the trifunctional protein on both alleles. This is in the LCHAD domain and substitutes glutamine for glutamic acid at position 474 of mature alpha subunit. The third child had this G1528C mutation on one allele and a different mutation (C1132T) creating a premature termination codon (residue 342) on the second allele. Our results demonstrate that mutations in the LCHAD domain of the trifunctional protein alpha subunit in affected offspring are associated with maternal acute fatty liver of pregnancy. This is the initial delineation of the molecular basis of isolated LCHAD deficiency. << Less

  Proc. Natl. Acad. Sci. U.S.A. 92:841-845(1995) [PubMed] [EuropePMC]

• beta-Oxidation enzymes in fibroblasts from patients with 3-hydroxydicarboxylic aciduria.

  Venizelos N., Ijlst L., Wanders R.J., Hagenfeldt L.

  The activities of 3-hydroxyacyl-CoA dehydrogenase, enoyl-CoA hydratase, and 3-ketoacyl-CoA thiolase were measured in fibroblasts from eight patients with 3-hydroxydicarboxylic aciduria. Measurement of 3-hydroxyacyl-CoA dehydrogenase with 3-ketopalmitoyl-CoA as substrate provided conclusive evidenc ... >> More

  The activities of 3-hydroxyacyl-CoA dehydrogenase, enoyl-CoA hydratase, and 3-ketoacyl-CoA thiolase were measured in fibroblasts from eight patients with 3-hydroxydicarboxylic aciduria. Measurement of 3-hydroxyacyl-CoA dehydrogenase with 3-ketopalmitoyl-CoA as substrate provided conclusive evidence for a deficiency of the long-chain 3-hydroxyacyl-CoA dehydrogenase in seven of the patients. Measurement of the enzyme in the normal direction cannot be recommended because this gives a higher residual activity. A trifunctional enzyme protein is responsible for the 3-hydroxyacyl-CoA dehydrogenase as well as for the hydratase and thiolase activities. A slight decrease in one or both of the other two activities was observed in four of the seven deficient patients, indicating that a defect in the trifunctional enzyme protein may affect the three enzyme activities to different degrees. << Less

  Pediatr Res 36:111-114(1994) [PubMed] [EuropePMC]