Presumed to be a dehydrogenase, but possibly an oxidase. Participates in limited purine salvage (requires aspartate) but does not support aerobic growth on purines as the sole carbon source (purine catabolism) (By similarity). H2O + NAD(+) + xanthine = H(+) + NADH + urate H2O + hypoxanthine + NAD(+) = H(+) + NADH + xanthine Purine metabolism; hypoxanthine degradation; urate from hypoxanthine: step 1/2. Purine metabolism; hypoxanthine degradation; urate from hypoxanthine: step 2/2. Heterotrimer of XdhA, XdhB and XdhC.