Abstract |
The metabolism of docosahexaenoic acid (22:6(n-3)) and adrenic acid (22:4(n-6)) was studied in cultured fibroblasts from patients with the Zellweger syndrome, X-linked adrenoleukodystrophy ( X-ALD) and normal controls. It was shown that [4,5- 3H]22:6(n-3) is retroconverted to labelled eicosapentaenoic acid (20:5(n-3)) in normal and X-ALD fibroblasts, while this conversion is deficient in Zellweger fibroblasts. [U- 14C] Eicosapentaenoic acid (20:5(n-3)) is elongated to docosapentaenoic acid (22:5(n-3)) in all three cell lines. With [U- 14C]20:5(n-3) as the substrate, shorter fatty acids were not detected. With [4,5- 3H]22:6(n-3) as the substrate, labelled fatty acids were esterified in the phospholipid- and triacylglycerol-fraction to approximately the same extent in all three cell lines. [2- 14C] Adrenic acid (22:4(n-6)) was desaturated to 22:5(n-6) and elongated to 24:4(n-6) in all three cell lines and to the largest extent in the Zellweger fibroblasts. This agrees with the view that the delta 4-desaturase is not a peroxisomal enzyme. The observation that the retroconversion of 22:6(n-3) to 20:5(n-3) is deficient in Zellweger fibroblasts strongly suggest that the beta-oxidation step in the retroconversion is a peroxisomal function. Peroxisomal very-long-chain ( lignoceroyl) CoA ligase is probably not required for the activation of 22:6(n-3), since the retroconversion to 20:5(n-3) is normal in X-ALD fibroblasts.
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Authors | M Grønn, E Christensen, T A Hagve, B O Christophersen |
Journal | Biochimica et biophysica acta
(Biochim Biophys Acta)
Vol. 1044
Issue 2
Pg. 249-54
(May 22 1990)
ISSN: 0006-3002 [Print] Netherlands |
PMID | 2140517
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Docosahexaenoic Acids
- Eicosapentaenoic Acid
- Fatty Acid Desaturases
- Linoleoyl-CoA Desaturase
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Topics |
- Adrenoleukodystrophy
(metabolism)
- Cells, Cultured
- Docosahexaenoic Acids
(metabolism)
- Eicosapentaenoic Acid
(metabolism)
- Fatty Acid Desaturases
(metabolism)
- Fibroblasts
- Humans
- Linoleoyl-CoA Desaturase
- Zellweger Syndrome
(enzymology, metabolism)
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