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Docosahexaenoic and arachidonic acid peroxidation: it's a within molecule cascade

Journal Article


Abstract


  • Peroxidation is a well-known natural phenomenon associated with both health and disease. We compared the peroxidation kinetics of phosphatidylcholine (PC) molecules with different fatty acid compositions (i.e. 18:0, 18:1n-9, 18:2n-6, 20:4n-6 and 22:6n-3 at the sn-2 and 16:0 at sn-1 position) either as molecules free in solution or formed into liposomes. Fatty acid levels, oxygen consumption plus lipid hydroperoxide and malondialdehyde production were measured from the same incubations, at the same time during maximal elicitable peroxidation. PCs with highly peroxidizable fatty acids (i.e. 20:4n-6 and 22:6n-3) in the same incubation were found to be either fully peroxidized or intact. Rates of peroxidation of PCs with multiple bisallylic groups (i.e. 20:4n-6 and 22:6n-3) peroxidized at 2-3 times the rate per bisallylic bond than the same phospholipid with 18:2n-6. The results suggest that propagation of peroxidation (H-atom transfer) is firstly an intramolecular process that is several-fold faster than intermolecular peroxidation. PCs in solution peroxidized twice as fast as those in liposomes suggesting that only half of the phospholipids in liposomes were available to peroxidize i.e. the outer leaflet. Experiments on liposomes suggest that even after heavy peroxidation of the outer leaflet the inner leaflet is unaffected, indicating how cells may protect themselves from external peroxidation and maintain control over internal peroxidation. Intramolecular peroxidation may produce highly concentrated, localized sites of peroxidation product that together with internal control of peroxidation of the inner leaflet of membranes provide new insights into how cells control peroxidation at the membrane level.

UOW Authors


  •   Else, Paul
  •   Kraffe, Edouard (external author)

Publication Date


  • 2015

Citation


  • Else, P. L. & Kraffe, E. (2015). Docosahexaenoic and arachidonic acid peroxidation: it's a within molecule cascade. BBA: Biomembranes, 1848 (2), 417-421.

Scopus Eid


  • 2-s2.0-84912119821

Ro Metadata Url


  • http://ro.uow.edu.au/ihmri/527

Has Global Citation Frequency


Number Of Pages


  • 4

Start Page


  • 417

End Page


  • 421

Volume


  • 1848

Issue


  • 2

Place Of Publication


  • Netherlands

Abstract


  • Peroxidation is a well-known natural phenomenon associated with both health and disease. We compared the peroxidation kinetics of phosphatidylcholine (PC) molecules with different fatty acid compositions (i.e. 18:0, 18:1n-9, 18:2n-6, 20:4n-6 and 22:6n-3 at the sn-2 and 16:0 at sn-1 position) either as molecules free in solution or formed into liposomes. Fatty acid levels, oxygen consumption plus lipid hydroperoxide and malondialdehyde production were measured from the same incubations, at the same time during maximal elicitable peroxidation. PCs with highly peroxidizable fatty acids (i.e. 20:4n-6 and 22:6n-3) in the same incubation were found to be either fully peroxidized or intact. Rates of peroxidation of PCs with multiple bisallylic groups (i.e. 20:4n-6 and 22:6n-3) peroxidized at 2-3 times the rate per bisallylic bond than the same phospholipid with 18:2n-6. The results suggest that propagation of peroxidation (H-atom transfer) is firstly an intramolecular process that is several-fold faster than intermolecular peroxidation. PCs in solution peroxidized twice as fast as those in liposomes suggesting that only half of the phospholipids in liposomes were available to peroxidize i.e. the outer leaflet. Experiments on liposomes suggest that even after heavy peroxidation of the outer leaflet the inner leaflet is unaffected, indicating how cells may protect themselves from external peroxidation and maintain control over internal peroxidation. Intramolecular peroxidation may produce highly concentrated, localized sites of peroxidation product that together with internal control of peroxidation of the inner leaflet of membranes provide new insights into how cells control peroxidation at the membrane level.

UOW Authors


  •   Else, Paul
  •   Kraffe, Edouard (external author)

Publication Date


  • 2015

Citation


  • Else, P. L. & Kraffe, E. (2015). Docosahexaenoic and arachidonic acid peroxidation: it's a within molecule cascade. BBA: Biomembranes, 1848 (2), 417-421.

Scopus Eid


  • 2-s2.0-84912119821

Ro Metadata Url


  • http://ro.uow.edu.au/ihmri/527

Has Global Citation Frequency


Number Of Pages


  • 4

Start Page


  • 417

End Page


  • 421

Volume


  • 1848

Issue


  • 2

Place Of Publication


  • Netherlands