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Biochim Biophys Acta. 2012 Mar;1817(3):410-8. doi: 10.1016/j.bbabio.2011.12.009. Epub 2011 Dec 27.

Brown adipose tissue mitochondria oxidizing fatty acids generate high levels of reactive oxygen species irrespective of the uncoupling protein-1 activity state.

Author information

1
Institut für Biochemie und Zellbiologie, Medizinische Fakultät, Otto-von-Guericke-Universität Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany. peter.schoenfeld@med.ovgu.de

Abstract

Mitochondria from brown adipose tissue (BATM) have a high enzymatic capacity for fatty acid oxidation and therefore are an ideal model to examine the sites of reactive oxygen species (ROS) generation during fatty acid oxidation. ROS generation by BATM (isolated from 3-week-old rats) was measured during acylcarnitine oxidation as release of H(2)O(2) into the medium and as inactivation of the matrix enzyme aconitase. The following results were obtained: (1) BATM release large amounts of H(2)O(2) in the coupled as well as in the uncoupled states, several times more than skeletal muscle mitochondria. (2) H(2)O(2) release is especially large with acylcarnitines of medium-chain fatty acids (e.g. octanoylcarnitine). (3) Reverse electron transport does not contribute in a significant extent to the overall ROS generation. (4) Despite the large release of H(2)O(2), the ROS-sensitive matrix enzyme aconitase is not inactivated during acylcarnitine oxidation. (5) In contrast to acylcarnitines, oxidation of α-glycerophosphate by BATM is characterized by large H(2)O(2) release and a pronounced aconitase inactivation. We hypothesize that acylcarnitine-supported ROS generation in BATM may be mainly associated with acyl-CoA dehydrogenase and electron transferring flavoprotein-ubiquinone reductase rather than with complexes of the respiratory chain.

PMID:
22226918
DOI:
10.1016/j.bbabio.2011.12.009
[Indexed for MEDLINE]
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