Table 1.

Enzyme activities of recombinant UGT76B1 toward ILA, LA, or SA.

	ILA	LA	SA
Km [mM]	0.472 ± 0.097	0.461 ± 0.079	0.151 ± 0.028
kcat [s-1]	0.914 ± 0.067	0.582 ± 0.035	0.331 ± 0.016
kcat/km [s-1 mM-1]	1.94	1.26	2.2

Enzyme reactions were performed using recombinantly expressed UGT76B1 and ¹⁴C-labeled UDP-glucose together with ILA or LA as aglycon substrates to obtain k_cat and K_m values (see section “Materials and Methods”; n = 4, ±SE). Values with SA were determined based on the absorption of SA and SA glucoside at 302 nm (see section “Materials and Methods”; n = 3, ±SE). While K_m values for ILA and LA were similar, k_cat were significantly different (t-test, p = 0.005). The derived enzymatic efficiencies k_cat/K_m are indicated as well.