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). Deletion results in increased adenine sensitivity, suggesting that this protein contributes to the conversion of adenine to guanine nucleotides during purine salvage. H2O + NAD(+) + xanthine = H(+) + NADH + urate H2O + hypoxanthine + NAD(+) = H(+) + NADH + xanthine Binds 1 Mo-molybdopterin (Mo-MPT) cofactor per subunit. 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. Is not solely regulated by nitrogen limitation. Belongs to the xanthine dehydrogenase family.