preferred_name: an anthocyanidin 3-O-[2-O-(4-coumaroyl)-alpha-L-rhamnosyl-(1->6)-beta-D-glucoside] + UDP-alpha-D-glucose <=> an anthocyanidin 3-O-[2-O-(4-coumaroyl)-alpha-L-rhamnosyl-(1->6)-beta-D-glucoside] 5-O-beta-D-glucoside + UDP + H(+)