Acts as a UDP-glucose:flavonol-3-O-glycoside-7-O-glucosyltransferase. 6- and 7-hydroxyflavone, but not 3- or 5-hydroxyflavone are accepted as substrates. Possesses low quercetin 3-O-glucosyltransferase, 7-O-glucosyltransferase and 4'-O-glucosyltransferase activities in vitro. Expressed in leaves and flowers, and at a very low level in roots. Belongs to the UDP-glycosyltransferase family. Was originally (Ref.1) thought to be a zeatin O-glucosyltransferases and was named ZOG2.