Reaction catalyzed by xylan alpha-1,2-glucuronosidase (3.2.1.131), alpha-glucuronidase (3.2.1.139)

		+		H2O	=			+
	aldotriouronic acid	+		H2O	=		4-O-methyl-alpha-D-glucuronic acid	+		Xylbeta(1-4)Xylbeta(1-4)Xyl