Effect of branched-chain keto-acids and dietary protein content on the activity of branched-chain amino acid transferase in rat tissues.
Rats fed branched-chain keto-acids in place of branched-chain amino acids exhibited increased specific activity of branched-chain amino acid transferase (BATase) in muscle, intestine, brain and liver as compared with controls fed sufficient diet to achieve comparable weight gain. This increase was observed whether or not methionine and phenylalanine were also replaced by their N-free analogues. Kidney BATase was unaffected. Rats fed a protein-free diet exhibited higher BATase specific activity in kidney, brain, liver and intestine than rats fed diets containing 6% casein; but little change in specific activity in these organs was seen as casein intake was progressively increased from 6% to 18%. Muscle BATase specific activity was the same between 0 and 18% dietary casein. The results show that branched-chain keto-analogues augment BATase in several tissues, including muscle. In contrast, varying casein intake from 6% to 18% had little effect, although protein-feeding augments BATase in some organs.
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002364:Caseins / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D007651:Keto Acids / Q000378:metabolism / Q000494:pharmacology*; D009928:Organ Specificity; D051381:Rats; D013329:Structure-Activity Relationship; D014018:Tissue Distribution; D000637:Transaminases / Q000378:metabolism*
D000596:Amino Acids; D002364:Caseins; D004044:Dietary Proteins; D007651:Keto Acids; D000637:Transaminases