title: Inhibition of uricase by pyrimidine and purine drugs.
abstract: A number of barbiturates inhibit uricase from porcine liver competitively, the Ki, values being in the range 1 to 13 X 10(-3) mol/L. In general the Ki increases as the size of the substituents at C-5 increases. Theophylline also inhibits the enzyme competitively (Ki = 1 X 10(-3) mol/L) but theobromine and caffeine have no inhibitory action at 0.01 mol/L. A number of sulphonamides and some other heterocyclic compounds, at 10(-3) mol/L, do not inhibit uricase. The possible effects of such inhibition in clinical assays for plasma/serum urate are discussed but it is concluded that the compounds which were studied are unlikely to cause significant interference in the assay.
mesh_terms: D000818:Animals; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D011687:Purines / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013329:Structure-Activity Relationship; D013552:Swine; D014503:Urate Oxidase / Q000037:antagonists & inhibitors*
chemical_list: D011687:Purines; D011743:Pyrimidines; D014503:Urate Oxidase