1.17.1.4	2 2-hydroxypurine + 2 NAD+ + 2 H2O	considerable activity	
1.17.1.4	2 hypoxanthine + 2 NAD+ + 2 H2O	preferred substrate	
1.17.1.4	2-amino-4-hydroxy-pterin + NAD+ + H2O	i.e. pterin	
1.17.1.4	2-amino-4-hydroxy-pterin + NAD+ + H2O	conversion of xanthine dehydrogenase to xanthine oxidase is strongly influenced by in vitro cell culture of alveolar epithelial cells	
1.17.1.4	2-amino-4-hydroxy-pterin + NAD+ + H2O	11% of the activity compared to xanthine	
1.17.1.4	3 purine + 3 NAD+ + 3 H2O	poor substrate	
1.17.1.4	6,8-dihydroxypurine + NAD+ + H2O	-	
1.17.1.4	6,8-dihydroxypurine + O2	-	
1.17.1.4	guanine + NAD+ + H2O	81.3% of the activity compared to hypoxanthine	
1.17.1.4	hypoxanthine + 2 NAD+ + 2 H2O	-