Arxula adeninivorans xanthine oxidoreductase and its application in the production of food with low purine content

Aims: Isolation and characterization of xanthine oxidoreductase and its application in the production of food with low purine content. Methods and Results: The A. adeninivorans xanthine oxidoreductase is an inducible enzyme. The best inducers were identified by enzyme activity tests and real-time PCR and used to produce large amounts of the protein. Xanthine oxidoreductase was partially purified and biochemically characterized, showing pH and temperature optimum of 8.5 and 43 degrees C, respectively. The enzyme decreased xanthine and hypoxanthine concentrations in yeast extract and was active simultaneously with other purine-degrading enzymes so that all of the substrates for uric acid production were reduced in a single step. Conclusions: It was shown that induced A. adeninivorans can produce sufficient amount of xanthine dehydrogenase and that the enzyme is able to reduce xanthine and hypoxanthine content in food, and when used in conjunction with other enzymes of the pathway, uric acid concentration is significantly reduced. Significance and Impact of the Study: Reduction in dietary purines is recommended to people suffering from hyperuricemia. Elimination of most purine-rich foods may affect balanced nutrition. Food with lowered purine concentration will assist in controlling the disease. This study is a continuation of previous studies that characterized and overexpressed other enzymes of the purine degradation pathway.