Fatty acid oxidation in brain is limited by the low activity of 3-ketoacyl-CoA thiolase

Conference · Fri May 01 04:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6073861

Yang, S; He, X; Schulz, H

In an attempt to establish why the brain is virtually incapable of oxidizing fatty acids, the activities of the ..beta..-oxidation enzymes in rat brain and rat heart mitochondria were measured and compared with each other. Although the apparent K/sub m/ values and chain-length specificities of the brain and heart enzymes are similar, the specific activities of all but one brain enzyme are between 4% and 50% of those observed in heart mitochondria. The exception is 3-ketoacyl-CoA thiolase (EC 2.3.1.16) whose specific activity in brain mitochondria is 125-times lower than in heart mitochondria. The partially purified brain 3-ketoacyl-CoA thiolase was shown to be catalytically and immunologically identical with the heart enzyme. The low rate of fatty acid oxidation in brain mitochondria estimated on the basis of palmitoylcarnitine-supported respiration and (1-/sup 14/C)palmitoylcarnitine degradation may be the consequence of the low activity of 3-ketoacyl-CoA thiolase. Inhibition of (1-/sup 14/C)palmitoylcarnitine oxidation by 4-bromocrotonic acid proves that the observed oxidation of fatty acids in brain is dependent on 3-ketoacyl-CoA thiolase and thus occurs via ..beta..-oxidation. Since the reactions catalyzed by carnitine palmitoyltransferase (EC 2.3.1.21) and acyl-CoA synthetase (EC 6.2.1.3) do not seem to restrict fatty acid oxidation in brain, it is concluded that the oxidation of fatty acids in rat brain is limited by the activity of the mitochondrial 3-ketoacyl-CoA thiolase.

• Research Organization: City College of CUNY, NY
• OSTI ID: 6073861
• Report Number(s): CONF-870644-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 46:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BIOLOGICAL PATHWAYS
BODY
BRAIN
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
CENTRAL NERVOUS SYSTEM
CHEMICAL REACTIONS
COENZYMES
ENZYME ACTIVITY
ENZYMES
HEART
INHIBITION
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MITOCHONDRIA
NERVOUS SYSTEM
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
OXIDATION
OXIDOREDUCTASES
RATS
RODENTS
TRACER TECHNIQUES
VERTEBRATES