In enzymology, a flavonol-3-O-glycoside glucosyltransferase is an enzyme that catalyzes the chemical reaction UDP-glucose + a flavonol 3-O-beta-D-glucosyl--beta-D-glucoside ⇌ {\displaystyle \rightleftharpoons } UDP + a flavonol 3-O-beta-D-glucosyl--beta-D-glucosyl--beta-D-glucosideThus, the two substrates of this enzyme are UDP-glucose and [[flavonol 3-O-beta-D-glucosyl--beta-D-glucoside]], whereas its 3 products are UDP, flavonol, and [[3-O-beta-D-glucosyl--beta-D-glucosyl--beta-D-glucoside]]. Wikipedia