Polarographische Bestimmung von Hydroperoxiden in Ölen

Niederstebruch, A.; Hinsch, I.

doi:10.1002/lipi.19670690902

Cited by 5 publications

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Pea mitochondrial lipids and their oxidation during mitochondria swelling

Haydar

Hadziyev

1974

J Sci Food Agric

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The composition and oxidation of lipids in pea mitochondria induced by swelling in presence of some transitional metal ions and ascorbic acid has been studied.Among the major mitochondrial lipids found were phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and diphosphatidylglycerol. The major fatty acids present in these lipids were linoleic, oleic and palmitic acids. The average unsaturation for mitochondria total fatty acids, expressed as Double Bond Index was 1.44, while the unsaturation for fatty acids of individual lipids varied between 1.02 and 1.73 being highest for an unidentified phospholipid and 1.44 for phosphatidylcholine present in mitochondria as the major lipid.Mitochondria isolated from pea seeds germinated for 4 days were found to be tightly coupled and to have an ADP/O ratio of 1.3. The swelling assay in 0.1 M-KCl for 1-day-old mitochondria has shown a swelling ability matching those of 4 and up to 8 days of age. Isolated mitochondria aged for 24 h at 2-4" C showed a swelling comparable to that of the fresh preparation. Swelling in the presence of ascorbic acid did not induce mitochondrial lipid oxidation. However, this was brought about in the presence of Cu2+ ions. The presence of Fez+ ions induced the highest degree of oxidation, and instead of a concurrent swelling, it induced contraction. At the same level of ions, Fez+ was more effective than Fe3+. Contrary to iron used at 4% of its physiological level, Mn2+ and Co2+ used at 12 to 24% of their levels found in pea seeds were ineffective in inducing oxidation. Nevertheless, the degree of mitochondrial swelling was highest in the medium containing KCl, lower in the presence of Co2+ and ascorbic acid and lowest in the presence of Fe3+. These results suggested that mitochondrial lipid oxidation does not depend on the degree of swelling.The lipid peroxides formed within mitochondria, up to 8 mg of mitochondrial protein, could not be detected by dropping mercury electrode polarography but were readily determined colorimetrically using thiobarbituric acid reagent.

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