Reaction catalyzed by rhamnogalacturonan I rhamnosyltransferase (2.4.1.351)

		+			=			+
	UDP-beta-L-rhamnose	+		alpha-D-galacturonosyl-[(1->2)-alpha-L-rhamnosyl-(1->4)-alpha-D-galacturonosyl]n	=		UDP	+		[(1->2)-alpha-L-rhamnosyl-(1->4)-alpha-D-galacturonosyl]n+1