Reaction catalyzed by guanosine-5'-triphosphate,3'-diphosphate phosphatase (3.6.1.40)

		+		H2O	=			+
	guanosine 5'-triphosphate,3'-monophosphate	+		H2O	=		guanosine 5'-diphosphate,3'-monophosphate	+		phosphate