The effect of hexokinase and tricarboxylic acid-cycle intermediates on fatty acid oxidation and formation of ketone bodies by rat-liver mitochondria.
1. The oxidation of butyrate, hexanoate and octanoate by rat-liver mitochondria suspended in a tris-potassium chloride medium in the presence of malate and serum albumin has been investigated. 2. The oxidation of butyrate to acetoacetate was markedly decreased by the addition of a system competitive for ATP (hexokinase-glucose). 3. Serum albumin or tricarboxylic acid-cycle intermediates prevented the inhibition by hexokinase and in their presence a greater proportion of the oxygen consumption was contributed by the tricarboxylic acid cycle. The results suggest that the energy supply for fatty acid activation is either compartmentalized in a spatial or kinetic sense or there exists a special activating mechanism not involving ATP. 4. Malate and other tricarboxylic acid-cycle intermediates caused substantial reduction (to beta-hydroxybutyrate) of the acetoacetate formed during the oxidation of butyrate, hexanoate and octanoate.
D000818:Animals; D002087:Butyrates / Q000378:metabolism*; D002951:Citrates / Q000494:pharmacology*; D002952:Citric Acid Cycle; D005227:Fatty Acids / Q000378:metabolism*; D005971:Glutamates / Q000494:pharmacology*; D006593:Hexokinase / Q000494:pharmacology*; D066298:In Vitro Techniques; D007656:Ketoglutaric Acids / Q000494:pharmacology*; D007657:Ketone Bodies / Q000096:biosynthesis*; D008099:Liver / Q000166:cytology; D008293:Malates / Q000494:pharmacology*; D008928:Mitochondria / Q000378:metabolism*; D051381:Rats; D012709:Serum Albumin / Q000494:pharmacology; D013386:Succinates / Q000494:pharmacology*
D002087:Butyrates; D002951:Citrates; D005227:Fatty Acids; D005971:Glutamates; D007656:Ketoglutaric Acids; D007657:Ketone Bodies; D008293:Malates; D012709:Serum Albumin; D013386:Succinates; D006593:Hexokinase