Further characterization of the heat-stable factor in the alpha-hydroxylation and oxidation of lignoceric acid in brain: effect of acidic amino acids and hexose-phosphates on brain fatty acid metabolism.
Lignoceric acid and other very long-chain fatty acids are converted to alpha-hydroxy fatty acids and ceramide in brain. These fatty acids are also oxidized and produce glutamic acid and other water-soluble products. All of these metabolic conversions are catalyzed by a rat brain particulate fraction and require NADPH, heat-labile factor, and heat-stable factor. The heat-stable factor was prepared from calf cerebellum. Glucose 6-phosphate and N-acetylaspartic acid have previously been identified as active components of the heat-stable factor. We report in this manuscript that glutamic acid, glutamine, aspartic acid, and gamma-aminobutyric acid as well as inorganic phosphate and adenosine nucleotides are also active components of the heat-stable factor. When the amino acids, glucose 6-phosphate, AMP, and phosphoric acid were combined, full activity of the heat-stable factor for the formation of cerebronate (by alpha-hydroxylation) and glutamate (presumably by beta-oxidation) from lignoceric acid was recovered. The role of the acidic amino acids in the metabolic conversion of lignoceric acid in brain appears to be their conversion to the corresponding alpha-keto acids and then incorporation into the TCA cycle. Glucose 6-phosphate is also likely to be involved in the TCA cycle through the Emden-Meyerhof pathway. Inorganic phosphate and AMP seemingly are used to produce ATP. However, the addition of up to 20 mM ATP alone did not replace the heat-stable factor.
D000596:Amino Acids / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism*; D005958:Glucosephosphates / Q000494:pharmacology; D006600:Hexosephosphates / Q000494:pharmacology; D006900:Hydroxylation; D009243:NAD / Q000494:pharmacology; D009249:NADP / Q000494:pharmacology; D009711:Nucleotides / Q000494:pharmacology; D010084:Oxidation-Reduction; D010710:Phosphates / Q000494:pharmacology; D051381:Rats
D000596:Amino Acids; D005227:Fatty Acids; D005958:Glucosephosphates; D006600:Hexosephosphates; D009711:Nucleotides; D010710:Phosphates; D009243:NAD; D009249:NADP; C010210:lignoceric acid