Fig. 2

The steviol products of the sugar transfers by UGT76G1. a–d HPLC traces of the reactions of STB, Reb A, ST, Reb E were analyzed, respectively, by HPLC. The five HPLC traces from top to bottom represent the following reaction conditions: no enzyme for 18 h (black), 0.03 mg ml⁻¹ enzyme (1×) for 2 h (blue), 0.03 mg ml⁻¹ enzyme (1×) for 18 h (purple), 0.15 mg ml⁻¹ enzyme (5×) for 2 h (green) and 0.15 mg ml⁻¹ enzyme (5×) for 18 h (red). The product is identified by the authentic standard. The yields of the products are related to the enzyme concentration and the reaction duration. The reactions catalyzed by UGT76G1 are shown in the box