Functional Characterization of a New Tea (<i>Camellia sinensis</i>) Flavonoid Glycosyltransferase Xianqian Zhao Peiqiang Wang Mingzhuo Li Yeru Wang Xiaolan Jiang Lilan Cui Yumei Qian Juhua Zhuang Liping Gao Tao Xia 10.1021/acs.jafc.6b05619.s001 https://acs.figshare.com/articles/journal_contribution/Functional_Characterization_of_a_New_Tea_i_Camellia_sinensis_i_Flavonoid_Glycosyltransferase/4724047 Tea (<i>Camellia sinensis</i>) is an important commercial crop, in which the high content of flavonoids provides health benefits. A flavonoid glycosyltransferase (CsUGT73A20), belonging to cluster IIIa, was isolated from tea plant. The recombinant CsUGT73A20 in <i>Escherichia coli</i> exhibited a broad substrate tolerance toward multiple flavonoids. Among them, kaempferol was the optimal substrate compared to quercetin, myricetin, naringenin, apigenin, and kaempferide. However, no product was detected when UDP-galactose was used as the sugar donor. The reaction assay indicated that rCsUGT73A20 performed multisite glycosidation toward flavonol compounds, mainly forming 3-<i>O</i>-glucoside and 7-<i>O</i>-glucoside in vitro. The biochemical characterization analysis of CsUGT73A20 showed more K7G product accumulated at pH 8.0, but K3G was the main product at pH 9.0. Kinetic analysis demonstrated that high pH repressed the glycosylation reaction at the 7-OH site in vitro. Besides, the content of five flavonol-glucosides was increased in CsUGT73A20-overexpressing tobaccos (<i>Nicotiana tabacum</i>). 2017-02-21 00:00:00 substrate glucoside Camellia sinensis 3G CsUGT 73A content K 7G product flavonoid 7- OH site Flavonoid Glycosyltransferase Tea CsUGT 73A tobaccos pH 9.0. Kinetic analysis