Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.17.1.4 (xanthine dehydrogenase)
 1,236 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Changes in hepatic purine enzyme activities of chicks fed diets containing 11%, 20%, 43% and 80% protein were correlated with protein intake and uric acid production in order to identify those enzymes with activities that parallel closely and may regulate uric acid production. Nucleoside phosphorylase, xanthine dehydrogenase, adenylosuccinate synthetase and adenosine kinase correlated positively with protein intake and uric acid production. Adenosine deaminase, 5'-nucleotidase (AMP), adenylate deaminase and adenine phosphoribosyltransferase correlated negatively with protein intake and uric acid production. Hypoxanthine phosphoribosyltransferase and 5'-nucleotidase (IMP) were unaffected by protein intake and did not correlate with uric acid production. The ratio of adenosine kinase to adenosine deaminase correlated positively with protein intake and uric acid production. The increased activities of adenylosuccinate synthetase and adenosine kinase, along with the reduced activities of 5'-nucleotidase and adenylate deaminase, in liver from chickens fed the 80% compared with the 11% protein diet demonstrate enhanced synthesis of adenine nucleotides. Since adenine nucleotides are essential cofactors for de novo purine synthesis, it is proposed that adenylosuccinate synthetase, adenosine kinase, 5'-nucleotidase and adenylate deaminase are key enzymes involved in the regulation of purine biosynthesis.
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PMID:Protein intake, hepatic purine enzyme levels and uric acid production in growing chicks. 61 42

In ureotelic species, such as the rat, adaptive changes in metabolic flux and enzyme levels occur in the purine metabolic pathway when cells are rapidly growing. This is observed in both regenerating liver and in malignant tissues. The enzymes P-Rib-PP amidotransferase and IMP dehydrogenase increase in activity in both situations. The level of purine biosynthesis is much higher in uricotelic species, such as the chick, when compared to ureotelic animals. By treating immature roosters with the hormone beta-estradiol, it is possible to induce rapid liver growth, allowing comparison of the regulation of purine biosynthesis and interconversion in high metabolic rate cells with different roles for purine metabolism. The tissue activities of P-Rib-PP amidotransferase, xanthine dehydrogenase, adenylosuccinate synthetase and lyase, AMP deaminase, IMP dehydrogenase, and GMP synthetase did not rise in livers from estradiol-treated chicks, as compared to controls. However, the rate of de novo purine synthesis triples and the intracellular level of P-Rib-PP doubles within 24 h of treatment. The biosynthesis of GMP is elevated at 12 and 24 h, but the levels of soluble nucleotide pools do not change. These data indicate that regulation of the de novo purine pathway in uricotelic species in a high metabolic situation is at the level of substrate availability (P-Rib-PP) and not due to changes in enzyme level or to feedback inhibition.
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PMID:Regulation of purine biosynthesis and interconversion in the chick. 714 43