Quantitation of acyl-CoA and acylcarnitine esters accumulated during abnormal mitochondrial fatty acid oxidation.
We have used radio-high pressure liquid chromatography to study the acyl-CoA ester intermediates and the acylcarnitines formed during mitochondrial fatty acid oxidation. During oxidation of [U-14C]hexadecanoate by normal human fibroblast mitochondria, only the saturated acyl-CoA and acylcarnitine esters can be detected, supporting the concept that the acyl-CoA dehydrogenase step is rate-limiting in mitochondrial beta-oxidation. Incubations of fibroblast mitochondria from patients with defects of beta-oxidation show an entirely different profile of intermediates. Mitochondria from patients with defects in electron transfer flavoprotein and electron transfer flavoprotein:ubiquinone oxido-reductase are associated with slow flux through beta-oxidation and accumulation of long chain acyl-CoA and acylcarnitine esters. Increased amounts of saturated medium chain acyl-CoA and acylcarnitine esters are detected in the incubations of mitochondria with medium chain acyl-CoA dehydrogenase deficiency, whereas long chain 3-hydroxyacyl-CoA dehydrogenase deficiency is associated with accumulation of long chain 3-hydroxyacyl- and 2-enoyl-CoA and carnitine esters. These studies show that the control strength at the site of the defective enzyme has increased. Radio-high pressure liquid chromatography analysis of intermediates of mitochondrial fatty acid oxidation is an important new technique to study the control, organization and defects of the enzymes of beta-oxidation.
Kler
R S
RS
Division of Clinical Neurosciences, Medical School, University of Newcastle upon Tyne, United Kingdom.
Jackson
S
S
Bartlett
K
K
Bindoff
L A
LA
Eaton
S
S
Pourfarzam
M
M
Frerman
F E
FE
Goodman
S I
SI
Watmough
N J
NJ
Turnbull
D M
DM
D015094:3-Hydroxyacyl CoA Dehydrogenases / Q000172:deficiency / Q000378:metabolism; D000214:Acyl Coenzyme A / Q000378:metabolism*; D002331:Carnitine / Q000378:metabolism*; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D044927:Electron-Transferring Flavoproteins; D004952:Esters / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism*; D005420:Flavoproteins / Q000378:metabolism; D006801:Humans; D008661:Metabolism, Inborn Errors / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000378:metabolism; D010084:Oxidation-Reduction
D000214:Acyl Coenzyme A; D044927:Electron-Transferring Flavoproteins; D004952:Esters; D005227:Fatty Acids; D005420:Flavoproteins; D015094:3-Hydroxyacyl CoA Dehydrogenases; D016660:NAD(P)H Dehydrogenase (Quinone); D002331:Carnitine