Assessment of effects of amino acids and branched chain keto acids on leucine oxidation in human lymphocytes.
Effects of amino acids and branched chain keto acids on leucine transamination and oxidation were assessed in peripheral human lymphocytes. Isoleucine (80-200 mumol/l) and valine (250-500 mumol/l) diminished transamination and oxidation of leucine up to 25%, glutamine (50-1000 mumol/l) up to 55%. alpha-Ketoisocaproic acid (KIC; 200 mumol/l) augmented the activity state of branched chain keto acid dehydrogenase by 40%. It is concluded that in peripheral human lymphocytes (1) isoleucine, valine and glutamine are physiological inhibitors of leucine catabolism, and (2) leucine can promote its own degradation via KIC.
Schäfer
G
G
Department of Medicine, University of Göttingen, FRG.
Schauder
P
P
D042942:3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide); D000293:Adolescent; D000328:Adult; D000409:Alanine / Q000494:pharmacology; D000596:Amino Acids / Q000494:pharmacology*; D005260:Female; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D005973:Glutamine / Q000494:pharmacology; D005998:Glycine / Q000494:pharmacology; D006801:Humans; D007532:Isoleucine / Q000494:pharmacology; D007651:Keto Acids / Q000494:pharmacology*; D007658:Ketone Oxidoreductases / Q000097:blood*; D007930:Leucine / Q000097:blood*; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009097:Multienzyme Complexes / Q000097:blood*; D010084:Oxidation-Reduction / Q000187:drug effects; D014633:Valine / Q000494:pharmacology
D000596:Amino Acids; D005971:Glutamates; D007651:Keto Acids; D009097:Multienzyme Complexes; D007532:Isoleucine; D005973:Glutamine; D018698:Glutamic Acid; D007658:Ketone Oxidoreductases; D042942:3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide); D007930:Leucine; D014633:Valine; D000409:Alanine; D005998:Glycine