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SUMMARY: Urea and allantoin were accumulated by germinating spores of Geotrichum candidum in the presence of xanthine, uric acid or allantoin. The concentration of endogenous allantoin was 5 to 10 times higher than that of urea. The specific activities of uricase and allantoicase were increased about nine- and fivefold respectively by uric acid and allantoin. No induction of allantoinase and ureidoglycolase was detected. Results may suggest that the different levels of purine degradative enzyme during induction might favour allantoin accumulation and prevent urea from attaining a toxic concentration.

SUMMARY: Fusarium moniliforme utilized the purines hypoxanthine, xanthine and uric acid as sole nitrogen sources. Allantoin and urea supported relatively more growth. The methylated purines caffeine and theobromine were not utilized. Uric acid, allantoic acid, glyoxylic acid and ammonia were detected in culture filtrates. Xanthine dehydrogenase, uricase, allantoinase, allantoicase and urease were present in cell homogenates and cell-free extracts. Uric acid was degraded to allantoic acid via allantoin.

SUMMARY: Five mutants were isolated at the all2 gene on the basis of their inability to utilize hypoxanthine as a sole source of nitrogen. These mutants failed to utilize the purines adenine, hypoxanthine, xanthine, uric acid, allantoin and allantoic acid, although they could utilize urea and ammonium. The all2 mutants appeared to be defective in purine induction of uricase, allantoinase, allantoicase and ureidoglycollase activities but retained wild-type activity of the constitutively synthesized urease. The all2 mutations were recessive.

SUMMARY: Penicillium chrysogenum utilized the purines hypoxanthine, xanthine, uric acid and adenine as sole nitrogen sources but not the methylated purines caffeine and theobromine. Cell-free extracts of this organism contained the enzymes xanthine dehydrogenase, uricase, allantoinase, allantoicase and urease. Uric acid was degraded to allantoic acid by way of allantoin; allantoin was degraded to glyoxylic acid by way of allantoic acid. Xanthine dehydrogenase, uricase, allantoinase and urease were constitutive whereas allantoicase was inducible by xanthine or allantoin.