Alterations in mitochondrial branched-chain amino acid metabolism in brain in acute hyperammonemic states.
Production of 14CO2 and [14C]branched-chain keto acids (BCKA) was determined from [U-14C]branched-chain amino acids along with the activities of branched-chain amino acid transaminase (BCAA-T) and branched-chain keto acid dehydrogenase (BCKA-DH) in mitochondria isolated from the cerebral cortex of normal and hyperammonemic rats. Results indicated that the production of CO2, but not of keto acids, was suppressed while the activities of BCAA-T and BCKA-DH were not adversely affected in the mitochondria of hyperammonemic rats. Suppression in the oxidation of BCAA in hyperammonemic states was found to be due to increased efflux of BCKA from mitochondria.
Alexander
J
J
Department of Physiology and Biophysics, University of Health Sciences, Chicago Medical School, IL 60064.
Murthy
C R
CR
D000594:Amino Acid Oxidoreductases / Q000378:metabolism; D000597:Amino Acids, Branched-Chain / Q000378:metabolism*; D000641:Ammonia / Q000097:blood* / Q000378:metabolism; D000818:Animals; D001923:Brain Chemistry / Q000502:physiology*; D002245:Carbon Dioxide / Q000378:metabolism; D002540:Cerebral Cortex / Q000201:enzymology / Q000378:metabolism; D066298:In Vitro Techniques; D050803:Leucine Dehydrogenase; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism*; D010084:Oxidation-Reduction; D051381:Rats; D017208:Rats, Wistar; D000637:Transaminases / Q000378:metabolism
D000597:Amino Acids, Branched-Chain; D002245:Carbon Dioxide; D000641:Ammonia; D000594:Amino Acid Oxidoreductases; D050803:Leucine Dehydrogenase; D000637:Transaminases; C019798:branched-chain-amino-acid transaminase