Adaptation of urate synthesis in chicken liver.
1. Urate synthesis was measured in hepatocytes from chickens after starvation or high-protein feeding. Adaptation occurred only on the high-protein diet. 2. The theoretical balances of reactions from alanine (5 alanine + 3 O2 = urate + 1.5 glucose + glycine) and asparagine (3 asparagine + 2 O2 = urate + ammonia + 0.5 glucose + glycine) agree reasonably well with the experimental results. 3. Enzymes directly involved in urate synthesis from these amino acids increase up to 12-fold on the high-protein diet; only amidophosphoribosyltransferase activity appears to be rate-limiting for urate synthesis. 4. The processes of nitrogen disposal in chicken and rat are compared and discussed.
D000409:Alanine / Q000378:metabolism; D000818:Animals; D001216:Asparagine / Q000378:metabolism; D002645:Chickens / Q000378:metabolism*; D004032:Diet; D004044:Dietary Proteins / Q000494:pharmacology; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism; D013217:Starvation / Q000201:enzymology; D014527:Uric Acid / Q000096:biosynthesis*
D004044:Dietary Proteins; D014527:Uric Acid; D001216:Asparagine; D009584:Nitrogen; D000409:Alanine