Reaction catalyzed by fructose 5-dehydrogenase (1.1.5.14)

		+			=			+
	D-fructose	+		[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide]	=		5-dehydro-D-fructose	+		[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] formazan