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