UGT706C1 generated a single reaction peak with
either kaempferol or quercetin. The kaempferol
reaction product with UGT706C1 (P1 in Fig. 3) had
the same retention time and UV spectrum as that of
authentic kaempferol 3-O-glucoside, and the quercetin
reaction product (P2 in Fig. 3) has the same as
retention time and UV spectrum as authentic
quercetin 3-O-glucoside. Thus, UGT706C1 is a
flavonoid 3-O-glucosyltransferase. UGT706C1 preferentially
uses kaempferol over quercetin