Reaction catalyzed by adenosine deaminase (3.5.4.4)

		+		H2O	=			+		NH3
	formycin A	+		H2O	=		2-(hydroxymethyl)-5-(1H-pyrazolo[4,3-d]pyrimidin-3-yl)tetrahydrofuran-3,4-diol	+		NH3