Specific activity of UGT74D1 toward auxins and related substrates.

Note: The assay mix (100 µl) contained 2 ug of purified UGT74D1 fusion protein, 5 mM UDP-glucose, 1 mM hormone, 50 mM HEPES (pH 7.0), 2.5 mM MgSO4, 10 mM KCl and 14.4 mM 2-mercaptoethanol. The reactions were carried out at 37°C for 3 h. The results represent the means ±S.D from three independent measurements. The specific enzyme activity was defined as nmol of substrates converted into glucose conjugates per second (nanokatal, nkat) by 1 mg of protein.