Brain mitochondria. V. Incorporation of fatty acids into phospholipids in bovine brain mitochondria

D S Beattie, R E Basford
1966 Journal of Biological Chemistry  
The incorporation of labeled palmitate into phospholipids in bovine brain mitochondria was compared with fatty acid oxidation under various experimental conditions. The rate of incorporation of palmitate into phospholipids proceeded at 20 to 25 % of the rate of palmitate oxidation under optimal conditions and required exogenous adenosine triphosphate and coenzyme A. The addition of coenzyme A was not necessary for fatty acid oxidation. In the presence of ATP, the incorporation into
more » ... n into phospholipids was not afIected by cyanide, dinitrophenol, or oligomytin, although these agents inhibited fatty acid oxidation. In the 'absence of exogenous nucleotides, oligomycin inhibited the incorporation of pahnitate into phospholipids and stimulated palmitate oxidation. A preincubation with glucose and hexokinase decreased the incorporation of palmitate into phospholipids to a greater extent than palmitate oxidation. The addition of oligomycin after the preincubation further inhibited the incorporation into phospholipids but reversed the inhibition of fatty acid oxidation. These results indicate that in brain mitochondria ATP is necessary for the activation of fatty acids before incorporation into phospholipids and that high energy intermediates are not involved. It is suggested that the activation of fatty acids before oxidation or esteriflcation may involve different energy sources and that these two metabolic processes may occur in separate compartments of the mitochondrion. The initial stage in the biosynthesis of neutral and phospholipids is an activation of the fatty acid and formation of an acylcoenzyme A. Wojtczak (1) has suggested that in rat liver mitochondria high energy intermediates of oxidative phosphorylation are involved in the activation of fatty acids preceding oxidation or incorporation into phospholipids. In the preceding paper (2), an activation of fatty acids by high energy
pmid:5935352 fatcat:trxwn6muxrdzbbae2je5lld4oi